THE 

CHAUTAUQUA 


CIRCLE 


WALKS  AMD  TALKS   , 

f  IN  THE  m^ 

GEOLOGICAL 
FIELD 


WINCHELL 


UNIVERSITY  OF  CALIFORNIA 
AT  LOS  ANGELES 


The  RALPH  D.  REED  LIBRARY 

DEPARTMENT  Or  GEOLOGY 

UNIVERSITY  of  CALIFORNIA 

LOS  ANGCLES.  CALIF. 


THE  CHAUTAUQUA  LITERARY   AND  SCIEN- 
TIFIC CIRCLE. 
jpoun&eti  in  1878. 

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For  all  information  concerning  the  C.  L.  8.  C.  address 

John  H.  Vincent,  Drawer  194,  Buffalo,  N.  Y. 

THE  REQUIRED  LITERATURE  FOR  1894-5. 

THE  GROWTH  OP  THE  ENGLISH  NATION  (illus- 
trated). Katharine  Coman,  Professor  of  History 
in  Wellesley  College $1.00 

THE  NINETEENTH  CENTURY  (illustrated).  H.  P. 
Judson,  Professor  of  Political  Science,  University 
of  Chicago 1.00 

FROM  CHAUCER  TO  TENNYSON  (with  portraits). 
Henry  A.  Beers,  Professor  of  English  Literature, 
Yale  University 1.00 

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W.  H.  Goodyear,  Lecturer  to  the  Brooklyn  Insti- 
tute   1.00 

WALKS  AND  TALKS  IN  THE  GEOLOGICAL  FIELD 
(illustrated).  Alexander  Winchell,late  Professor 
of  Geology,  University  of  Michigan  .  .  .  1.00 

THE  CHAUTAUQUAN  (12  numbers,  illustrated)       .     2.00 


Works  by  Alexander  Winchell. 

Walks  and  Talks  in  the  Geological  Field,  pp. 
vi  +  352,  13  illustrations. 

Geological  Excursions,  pp.  234,  88  illustrations. 

Geological  Studies,  pp.  500,  367  illustrations. 

World  Life,  pp.  xxiv  +  642,  59  illustrations. 

Sparks  from  a  Geologist's  Hammer,  pp.  400,  20 
illustrations. 

Sketches  of  Creation,  pp.  xii  +  459,  101  illus- 
trations. 

Preadamites,  pp.  xxvi  +  500. 

The  Doctrine  of  Evolution,  pp.  148. 

Reconciliation  of  Science  and  Religion,  pp.  xvi 
+  403. 

Shall  We  Teach  Geology  ?  pp.  329. 


Gbautauqua  IRea&tng  Circle  ^Literature 


WALKS  AND  TALKS 


IN  THE 


GEOLOGICAL   FIELD 


ALEXANDER  WINCHELL,   LL.D., 

Late  fi'ofessor  of  Geology  and  Palceontology  in  the  University  of  Michigan. 


REVISED  AND  EDITED  BY  FREDERICK  STARR,, ,  ,', 

Of  the  University  of  Chicago.  •'„  ^  „' 


FLOOD  AND  VINCENT 


MEADVILLE  PENNA 

150  FIFTH  AVE.  NEW  YORK 

1894 


146347 


The  required  books  of  the  C.  L.  S.  C.  are  recommended  by  a 
Council  of  six.  It  must,  however,  be  understood  that  rec- 
ommendation does  not  involve  an  approval  by  the  Council, 
or  by  any  member  of  it,  of  every  principle  or  doctrine 
contained  in  the  book  recommended. 


Copyright,  1894, 
By  FLOOD  &  VINCENT. 


*  *•     TTieJ-Chautauqua-Century  Press,  Meadville,  Pa.,  U.  8.  A. 
'.*,.  Eiieotrotyped,  Printed,  and  Bound  by  Flood  <fe  Vincent. 

•  ••e.   ."••• 


Geology 
Library 


PREFACE. 

IN  writing  this  book  for  Chautauqua  readers,  Dr. 
"VVinchell  desired  that  it  should  hold  a  position  between 
text-books  and  books  of  light  reading.  No  one  was 
better  qualified  than  he  to  prepare  such  a  volume.  In 
revising  the  work,  the  editor  has  left  it  as  entirely  Prof. 
Winchell' s  work  as  possible.  Although  a  number  of 
pages  have  been  cut  out,  it  is  believed  that  the  geo- 
logical material  is  all  retained  and  in  the  author's  own 
words.  Marginal  comment  has  been  introduced  as  a 
convenience  to  the  reader  and  a  few  footnotes  have  been 
added. 

The  illustrations  used  in  the  work,  with  two  excep- 
tions, have  been  furnished  through  the  kindness  of  Major 
J.  W.  Powell,  Director  of  the  U.  S.  Geological  Survey. 

The  reader  is  advised  to  read  the  book  in  sections  of 
related  chapters,  as  follows  : 

I. -VII.  —Surface  Geology :    The  Drift  and  its  origin. 

VIII. -XIII.— Strata  :  Their  origin,  contents,  and  po- 
sition. 

XIY.-XX. — Igneous  Agencies.     Elevatory  forces. 

XXI. -XXVI.— Economic  Geology  :  The  wealth  of 
the  hills. 

XXVII.  -XXXIV.  —Fossils. 


iv  Preface. 


XXXV. -XXXVIII. —Beginnings  of  the  Earth. 

XXXIX.-XLIX.— History  of  life  and  the  growth  of 
the  continent. 

Those  who  knew  and  loved  the  author  will  delight  in 
re-reading  his  work  ;  to  those  who  did  not  know  him 
these  Walks  and  Talks  will  be  in  some  degree  a  revela- 
tion of  a  true  and  noble  man. 

THE  EDITOR. 

Chicago,  Illinois,  December  2,  189S. 


CONTENTS. 

CHAPTER  PAGK 

I.  THE  GEOLOGY  AT  OUR  DOORS  -       7 

II.  LOST  ROCKS    -  11 

III.  THE  GRAVEL  PIT  -      17 

IV.  AMONG  THE  GLACIERS  24 
V.  THE  HILLSIDE  SPRING  AND  ITS  WORK  -      32 

VI.  INTRODUCTION  TO  THE  ROCKS    -  39 

VII.  THE  FLOODS  OF  THE  GREAT  LAKES  -     45 

VIII.  THE  MUD  FLAT  51 

IX.  THE  RIVER  GORGE                                -  57 

X.  A  WALK  UNDER  THE  SEA  64 

XL  BY  THE  ROCKY  WALL         -  71 

XII.  MYSTERIOUS  FORMS  OF  LIFE  78 

XIII.  COURSES  OF  THE  EARTH'S  MASONRY  -     85 

XIV.  A  WALK  IN  THE  YELLOWSTONE  PARK    -  93 
XV.  AMONG  THE  VOLCANOES       -  -    103 

XVI.  FROZEN  SEAS  OF  LAVA  -  -  111 

XVII.  IMPRISONED  HEAT  -    117 

XVIII.  THE  UNSTABLE  LAND  125 

XIX.  THE  FRAMEWORK  OF  THE  MOUNTAINS  -    132 

XX.  How  THE  MOUNTAIN  FRAMEWORK  is  REARED    139 

XXI.  DOWN  IN  A  MINE   -  -    145 

XXII.  THE  KING  OF  METALS  153 

XXIII.  THE  CRYSTALS  OF  THE  SEA       -•— ^=_  -    159 

XXIV.  LIQUID  SUNLIGHT  (Petroleum)  166 
XXV.  GASEOUS  SUNLIGHT  (Natural  Gas)     -  -    173 

XXVI.  SOLIDIFIED  SUNLIGHT  (Coal)      -  -  183 


Contents. 


CHAPTER  PAGE 

XXVII.  MONSTERS  OF  A  BURIED  WORLD  -    189 

XXVIII.  THE  CEMETERIES  OF  THE  BAD  LANDS  198 

XXIX.  LESSON  FROM  A  LUMP  OF  CHALK  -    206 

XXX.  LONE  BURIALS  IN  THE  COAL  LANDS  214 

XXXI.  TERRIBLE  FISHES  AND  THEIR  COMPANIONS    220 

XXXII.  ANCESTRY  OF  THE  PEARLY  NAUTILUS  227 

XXXIII.  THE   KING  CRAB'S   GRANDFATHER   AND 

OTHER  GRANDFATHERS  -    234 

XXXIV.  EARTH'S  DEEPEST  GRAVES  -  241 
XXXV.  AN  EARLIER  BEGINNING  -    247 

XXXVI.  GATHERING  WORLD  STUFF  253 
XXXVII.  THE  WHIRLING  FIRE-MIST  -    259 
XXXVIII.  THE  PRIMEVAL  STORM  265 
XXXIX.  THE  WAR  IN  THE  OCEAN  -    271 
XL.  THE  WORLD  WITHOUT  A  BACKBONE  278 
XLI.  THE  DYNASTY  OF  FISHES  -    283 
XLII.  SCENES  FROM  THE  COAL  PERIOD        •  290 
XLIII.  THE  REPTILE  MONARCHIES          -  -    296 
XLIV.  MAMMALIAN  RULE  303 
XLV.  ANTICIPATION  AND  RETROSPECT  IN  LIFE- 
PLANS   -  308 
XLVI.  THE  THROES  OF  THE  CONTINENT  -    316 
XLVII.  THE  REIGN  OF  ICE  324 
XLVIII.  A  GEOLOGIC  SPRING  TIME  -    333 
XLIX.  THE  EARTH  RECEIVES  HER  KING     -  340 


WALKS  AND  TALKS  IN  THE  GEO- 
LOGICAL FIELD. 

I.     THE  GEOLOGY  AT  OUR  DOORS. 

SURFACE  MATERIALS. 

GEOLOGY  is  the  story  of  the  earth  and  of  earth's  The  scope 
populations.    It  is  more  than  a  story  told  by  some 
narrator  to  whom  we  must  listen.     We  ourselves 
shall  weave  the  story.    We  will  ask  the  world  to 
tell  its  own  story. 

We  shall  travel  all  over  the  world.  We  shall  climb 
over  mountain-cliffs  and  descend  into  deep  mines. 
We  shall  go  down  under  the  sea,  and  make  the  ac- 
quaintance of  creatures  that  dwell  in  the  dark  and 
slimy  abysses.  We  shall  split  the  solid  rocks  and 
find  where  the  gold,  the  silver,  and  the  iron  are  hid- 
den. We  shall  open  the  stony  tombs  of  the  world's 
mute  populations.  We  shall  plunge  through  thou- 
sands of  ages  into  the  past,  and  shall  sit  on  a  pin- 
nacle and  see  this  planet  bathed  in  the  primitive 
ocean ;  boiled  in  the  seething  water ;  roasted  in  an- 
cient fires  ;  distorted,  upheaved,  moulded,  and  re- 
shaped again  and  again,  in  a  long  process  of  prepara- 
tion to  become  fit  for  us  to  dwell  upon  it.  We  shall 
see  a  long  procession  of  strange  creatures  coming  into 
view  and  disappearing — such  a  menagerie  of  curious 
beasts  and  crawling  and  creeping  and  flying  things 
as  never  yet  marched  through  the  streets  of  any 

7 


8         Walks  and  Talks  in  the  Geological  Field. 

town.  And  what  is  most  wonderful  of  all,  we  shall 
plunge  through  thousands  of  ages  of  coming  events, 
and  sit  on  our  pinnacle  and  see  the  world  grow  old — 
all  its  human  populations  vanished — its  oceans  dried 
up — its  sun  darkened,  and  silence  and  midnight  and 
Winter  reigning  through  the  entire  province  in 
which  a  sisterhood  of  planets  at  present  basks  in  the 
warmth  and  light  of  a  central  and  paternal  sun. 
Material  We  must  begin  at  the  beginning.  Those  who  go 
around  us  on  l°n£  anc*  pleasant  journeys  have  to  start  from 
their  own  doorsteps.  Geology  tells  all  about  this 
world.  The  world  is  here — under  our  feet.  It  is  in 
the  garden  and  along  the  roadside,  and  in  the  field, 
and  on  the  shore  where  the  summer  ripples  sing  lul- 
labies to  the  sleepy  crags,  and  winter  storms  tear 
them  from  their  resting-places.  No  summer  ripples 
or  wintry  storms  are  here  ;  but  the  solid  land  is  here. 
Let  us  walk  up  this  hill-slope  and  sit  where  we  may 
get  an  outlook  over  a  little  piece  of  the  world's  sur- 
face. 

What  is  there,  now,  within  reach  of  our  vision  that 
we  can  distinguish  and  describe  and  say  that  it  be- 
Scenery  is  longs  to  the  world — is  a  part  of  the  world  ?  Whatever 
jt  may  ke>  it  is  a  geological  fact.  It  is  a  part  of  the 
science  of  geology.  Now,  here  is  this  hill-slope,  and 
the  soil  and  stones  which  make  it.  Back  of  us  the 
hill  rises  to  a  higher  level.  Perhaps  brown  cliffs 
frown  near  its  summit ;  and  there  are  huge,  heavy 
trees  upborne  five  hundred  feet  above  the  town. 
But,  in  the  opposite  direction,  there  is  the  landscape. 
That  is  a  geological  fact.  With  all  its  scenic  beauty, 
that  is  geology,  at  foundation.  The  houses  and  the 
herds,  the  wheat-fields  and  the  gardens — these  are 


The  Geology  at  our  Doors. 


accessories.  But  the  dark,  beetle-browed  ridge  which 
skirts  the  horizon— that  is  nature's.  The  green  forest 
which  glides  down  to  the  field  borders  ;  the  stream 
which  winds  across  the  landscape,  and  rises  and  falls 
with  the  rains ;  the  low  swells  and  the  valleys  be- 
tween ;  the  outcropping  ledge  in  the  field,  and  the 
loose  stone  by  the  roadside — these  belong  to  nature. 
There,  in  the  distance,  flies  the  train  of  steam-cars, 
its  iron-bcund  way  has  been  cut  through  hill  and 
rock-mass,  and  opens  to  our  view  something  of  the 
hidden  material  which  goes  to  form  the  world. 
There  is  the  meadow,  with  its  green  turf,  and  deep, 
dark  soil.  The  gully  scored  in  the  hillside  by  the 
summer  storm,  and  the  train  of  stones  and  sand  at 
its  foot — which  the  water  tore  from  their  hiding- 
places  beneath  the  soil.  Up  the  stream  we  see  the 
tamarac  swamp  or  the  open  marsh,  through  which 
the  head-waters  flow — the  head-waters  of  the  main 
stream  or  of  some  small  tributary.  There,  just  be- 
yond, is  the  little  lake  or  pond,  sleeping  in  its  green- 
fringed  nest,  and  looking  out  on  the  grass-covered 
slopes  and  the  blue  sky. 

This  is  all  geology.  We  are  in  the  midst  of  it. 
We  have  been  enchanted  by  it  before  we  knew  its 
name.  We  have  admired  the  forms  fashioned  in 
beauty  by  the  hands  of  the  geological  forces  before 
we  knew  that  it  had  a  geological  origin,  or  pos- 
sessed any  geological  significance,  or  had  passed 
through  long  ages  of  preparation.  We  have  been 
like  children  born  in  the  parental  dwelling,  reared 
in  the  midst  of  its  comforts  and  adornments,  without 
once  thinking  that,  before  we  were  born,  some  mind 
planned  the  dwelling,  some  hands  reared  its  walls, 


10       Walks  and  Talks  in  the  Geological  Meld. 

laid  its  floors,  and  fashioned  every  doorway  and  cas- 
ing. The  green  slope  was  made  ;  the  pretty  lake  was 
scooped  out ;  the  swelling  hill  was  shaped  ;  the  dark 
mountain  was  upbuilt,  its  foundations  were  laid,  its 
vast  weight  has  been  sustained  and  is  to-day  sus- 
tained by  some  support,  with  strength  proportioned 
to  the  requirement.  It  is  time  for  us  to  come  to  a 
realization  of  these  facts. 

We  may  begin  in  this  very  spot  to  inquire  how 
this  terrestrial  home  was  fashioned.  It  was  made 
without  hands,  but  not  without  the  use  of  the  same 
forces  of  nature  and  properties  of  matter  as  were  em- 
ployed in  the  building  of  our  paternal  dwelling.  Its 
plan  was  not  drafted  on  paper  and  carried  out  under 
the  direction  of  a  builder,  who  issued  his  orders  in 
audible  tones  ;  but  our  terrestrial  abode  is  built  under 
a  plan  just  as  real  and  just  as  intelligible,  and  is  just 
as  truly  a  fit  subject  for  study.  There  is  this  differ- 
ence, that  we  may  arrive  at  a  complete  understand- 
ing of  the  plan  and  purposes  and  modes  of  con- 
struction of  the  paternal  home  ;  but  of  the  terrestrial 
home  we  can  only  arrive  at  an  incomplete  under- 
standing. 

its  mate-  If  we  decide  to  interest  ourselves  in  the  inquiry, 
first  study  ^ow  *ne  world  was  made  and  what  it  has  become, 
we  must  first  give  attention  to  the  materials  of 
which  it  is  composed.  It  is  a  stone  dwelling ;  it  is 
imperishable — at  least  as  imperishable  as  granite 
foundations  and  massive  courses  of  masonry  can 
render  a  structure.  Here  are,  indeed,  beds  of  gravel 
and  sand,  overspreading  the  greater  part  of  the 
country.  These  are  not  firmly  consolidated,  and 
are  easily  moved  out  of  place.  But  they  are  like 


Lost  Rocks.  11 


the  gravel  used  on  the  roofs  of  some  buildings — a 
very  insignificant  part  of  the  whole.  Underneath 
these  loose  materials  we  shall  find  the  solid  and  en- 
during foundations.  But  the  study  of  the  loose  sur- 
face materials  is  full  of  interest,  because  their  pres- 
ence renders  the  earth  habitable.  What  sort  of  a 
home  for  man  or  beast  would  this  planet  be,  if  all 
the  loose  surface  beds  were  cleared  off  down  to  the 
rocky  floor  on  which  they  rest?  Did  you  ever  hear 
that  question  asked  before?  We  must,  by  all  means, 
begin  with  the  stones,  and  sands,  and  clays,  which 
lie  upon  the  surface,  or  near  the  surface,  and  try  to 
ascertain  what  they  are  and  how  they  are  arranged, 
and  of  what  use  they  are  to  man. 


II.     LOST  BOCKS. 

BOWLDERS. 

WHO  cares  for  a  cobble-stone  ?  It  is  a  kind  of  Bowlders, 
nuisance  anywhere — so  most  people  think.  The  far- 
mer would  be  glad  to  have  every  one  of  them  carted 
from  his  fields.  I  have  seen  land  so  thickly  covered 
by  them  as  to  be  almost  impossible  to  cultivate.  You 
will  notice  that  cobble-stones  are  of  various  sizes.  In 
fact,  it  is  difficult  to  state  where  a  cobble-stone  is 
small  enough  to  be  called  a  "  pebble,"  and  just  where 
it  is  too  large  to  be  a  cobble-stone.  Pebbles  differ 
from  them  only  in  size.  Pebbles  are  hard  and  round- 
ed, and  seem  formed  of  the  same  kinds  of  rocks ; 
and  the  large,  rounded,  loose  stones,  which  lie  scat- 
tered over  the  earth's  surface,  are  in  every  respect 


12       Walks  and  Talks  in  the  Geological  Meld. 

only  a  larger  style  of  cobble-stones.  It  is  plain  that 
these  are  all  one  class  of  rocks.  So  it  has  been  de» 
cided  ;  and  geologists  call  them  bowlders.  This  is 
an  old  name  used  by  common  people  before  the 
science  of  geology  existed,  because  these  stones  are 
rounded  like  balls  or  bolls ;  and,  being  loose  on  the 
surface,  are  apt  to  be  bowled  about.  Even  grains  of 
gravel  and  sand  appear  to  be  of  the  same  nature  as 
bowlders.  You  will  also  notice,  especially,  that  these 
rocks  are  all  separate  and  detached,  as  well  as  round- 
ed, and  they  are  of  various  colors  and  mixtures  of 
colors.  They  are  apparently  different  kinds  of  rocks, 
which  by  some  means  have  been  brought  promis- 
cuously together.  Ledges  of  rock,  which  you  must 
The  origin  have  noticed  many  times,  are  generally  all  one  kind 
of  bowl-  Of  rock.  They  extend  long  distances,  and  continue 
under  the  earth.  Should  a  ledge  of  rocks  become 
broken  up,  and  the  fragments,  large  and  small,  have 
their  angles  rounded  off,  and  the  whole  then  be 
scattered  over  a  township,  far  from  the  ledge,  the  re- 
sult would  be  much  like  what  we  see  in  our  actual 
bowlders.  From  all  we  know  of  rocks  we  are  con- 
strained to  believe  that  our  bowlders  are  rounded 
fragments  of  broken  up  ledges.  But  where  are  the 
ledges?  Not  in  the  next  township  or  county.  Per- 
haps not  in  the  next  state  or  province.  They  have 
strayed  far  away  from  their  native  ledges.  They  are 
"  lost  rocks."  Now,  it  would  be  very  interesting  to 
know  where  the  parent  ledges  are  ;  and  it  is  curious 
how  these  fragments  have  been  transported  so  far, 
and  how  they  became  so  rounded,  instead  of  remain- 
ing angular,  like  the  stones  blasted  from  a  quarry. 
Indeed,  the  more  we  think  about  this,  the  more 


Lost  Rocks.  13 


astonishing  the  facts  appear;  for  we  call  to  mind  "Lost 

that  lust  such  bowlders  are  scattered  all  over  our  rocks  "are 

travelers. 

northern  states,  and  they  lie  buried  beneath  the  sur- 
face in  countless  numbers.  And  the  very  sand  and 
gravel,  to  the  depth  of  many  feet,  is  only  the  same 
kind  of  material  in  a  finer  state.  What  an  incalcula- 
ble amount  of  work  has  been  accomplished  in  trans- 
porting all  these  materials  so  far  that  the  places  from 
which  they  came  have  been  lost,  and  can  not  be 
found.  Suppose  it  were  necessary  to  cart  all  the  loose 
stuff  on  a  township  to  a  distance  only  one  mile  fur- 
ther, on  what  terms  do  you  think  the  contract  would 
be  taken  ?  But  all  that  stuff  has  been  moved — not 
one  mile  alone,  but  many  miles.  And  not  alone  the 
stuff  on  a  township,  but  the  stuff  on  ten  thousand 
townships.  The  work  was  not  done,  you  say,  by  the 
slow  process  of  hauling  in  carts.  No,  indeed  ;  but  it 
was  done  somehow,  and  it  is  the  same  job  whether 
performed  by  Nature's  method  or  by  human  muscle. 

What  do  you  imagine  was .  Nature's  method  ? 
Would  it  not  be  a  grand  discovery  if  we  could  find 
out?  It  was  Agassiz  that  ascertained  this,  and  the 
discovery  gained  him  great  fame.  Suppose  we  could 
stand  by  and  see  Nature  in  the  midst  of  the  job — 
carting  and  dumping  on  the  bare  surface  of  the  rocks, 
the  gravel  and  sand  and  clay  so  indispensable  to 
render  the  surface  of  the  earth  habitable  for  man  or 
beast  or  plant.  I  think  we  should  consider  it  a  grand 
revelation  of  the  method  and  mind  of  the  Author 
of  nature.  I  am  happy  to  assure  you  that  we  have 
found  out  pretty  precisely  how  this  immense  and 
beneficent  work  was  done. 

Many   bowlders  attain  to  dimensions  which  are 


14        Walks  and  Talks  in  the  Geological  Field. 

Some  great  truly  enormous.  The  largest  are  found  in  northern 
bowlders.  j^ew  England  and  Canada.  As  we  proceed  south- 
ward, the  average  size  diminishes,  and  south  of  the 
parallel  of  Cincinnati,  bowlders  are  entirely  wanting, 
except  along  the  Appalachians.  In  New  Hampshire 
are  many  immense  bowlders,  which  have  excited  the 
wonder  of  all  who  have  seen  them.  Several  of  these 
have  been  described  and  figured  by  Professor  C.  H. 
Hitchcock  in  his  Eeport  on  the  Geology  of  New 
Hampshire.  The  Churchill  Rock  of  Nottingham  is 
62  feet  long,  40  feet  wide  and  40  feet  high.  It  con- 
tains 75,000  cubic  feet,  and  weighs  6,000  tons.  Close 
by  is  Chase  Bock,  40  feet  long,  40  feet  high  and  30 
feet  wide.  Vessel  Rock,  in  Gilsum,  now  split  by 
frost,  weighed  2,286  tons.  The  Green  Mountain 
Giant,  in  Whittingham,  Vermont,  weighs  3,000  tons  ; 
and  a  bowlder  formerly  existing  at  Fall  River, 
Massachusetts,  weighed  5,400  tons.  At  St.  Ignace,  in 
the  Upper  Peninsula  of  Michigan,  lies  a  porphyry 
bowlder  25  feet  in  .height.  Mr.  G.  M.  Dawson,  in 
his  Report  on  the  Geology  of  the  Northwest  Terri- 
tory, describes  a  quartzite  bowlder  42  feet  long,  40  feet 
wide  and  20  feet  high,  and  another  nearly  as  large. 
It  appears  that  the  greater  part  of  North  America, 
down  to  the  latitude  of  Cincinnati,  id  overstrewn  by 
incoherent  materials  containing  bowlders.  The  situa- 
tion is  similar  in  Europe ;  and  there,  also,  certain 
"lost  rocks"  or  "erratics"  attain  vast  dimensions. 
The  "Pierre  a  bot"  (or  Toad-stone),  on  the  Jura 
Mountains,  about  two  miles  west  of  Neufchatel,  con- 
tains 40,000  cubic  feet,  and  weighs  3,000  tons.  As  far 
south  as  the  Lake  of  Como,  bowlders  of  large  size  are 
very  frequently  encountered. 


Lost  Rocks.  15 


Often  these  lost  rocks  lie  perched  on  the  summits  of  Rocking- 
sharp  cliffs  ;  and  sometimes  we  find  them  so  nicely  st<  nes- 
poised  that  the  strength  of  a  man  suffices  to  give 
them  a. tilt.  They  are  then  called  "  rocking  stones." 
In  Hanover,  New  Hampshire,  half  a  mile  east  of 
Dartmouth  College,  is  a  rocking  stone  12  feet  long,  10 
feet  wide,  5J  feet  thick,  containing  480  cubic  feet.  In 
Goffstown  is  one  8  feet  high  and  42  feet  in  circumfer- 
ence. In  Barre,  Massachusetts,  is  one  having  a 
smaller  bowlder  on  its  back,  which,  when  in  motion, 
suggests  the  idea  of  a  child's  rocking-horse.  One  in 
Fall  River,  poised  on  granite,  weighs  160  tons. 

We  find  bowdlers  at  various  altitudes,  from  the 
level  of  the  sea,  to  the  height  of  perhaps  six  thou- 
sand feet ;  but  above  this,  though  rock  fragments  are 
extremely  numerous,  they  are  mostly  angular,  and 
appear  to  be  derived  from  rocky  ledges  close  by. 
They  are  not  "lost  rocks."  The  summit  of  Mt. 
Washington  is  covered  by  a  bed  of  angular  frag- 
ments, and  such  fragments  are  common  for  two 
thousand  feet  below  the  summit.  Lower  than  this, 
rounded  bowlders  are  abundant.  Professor  C.  H. 
Hitchcock,  however,  thinks  he  finds  real  transported 
rocks  to  the  very  summit.  The  great  quartzite  bowl-  Bowldera 
der  in  the  Northwest  Territory,  Canada,  is  3,250  feet  of  high  el- 
above  sea-level.  Many  others  in  that  part  of  the  con-  ev 
tinent  are  up  to  4,400  feet  in  elevation  ;  and  in  one 
region,  attain  5,280  feet.  Some  erratics  on  the  flanks 
of  the  Sweet  Grass  Hills  lie  at  an  elevation  of  4,660 
feet.  The  Pierre  a  bot,  in  Switzerland,  is  800  feet 
above  Lake  Neufchatel,  which  lies  itself  1,427  feet 
above  sea-level. 

We  observe,  in  passing  over  the  country,  that  the 


16       Walks  and  Talks  in  the  Geological  Field. 

larger  bowlders  are  northward  ;  while  toward  the 
south» their  avera£e  size  diminishes  to  cobble-stones, 
and  finally,  all  indications  of  transported  rocks  dis- 
appear. Since  we  have  concluded  that  all  these  lost 
rocks  have  been  removed  from  extensive  ledges  some- 
where, it  seems  probable  that  the  direction  of  these 
ledges  is  to  the  north.  We  notice  also,  that  bowlders 
of  any  particular  kind  become  more  numerous,  as 
well  as  larger,  as  we  proceed  northward.  In  fact, 
in  some  cases,  by  following  up  a  train  of  bowlders  of 
a  particular  kind,  we  trace  them  to  their  origin. 
That  origin  is  often  sixty  or  one  hundred  miles,  or 
even  two  hundred  miles  away.  It  is  not  always  pos- 
sible to  trace  bowlders  to  their  source  by  following 
back  a  train.  But  we  can  always  consider  where  is 
the  nearest  locality  of  bed-rocks  of  the  same  kind  as 
any  particular  bowlders.  For  instance,  in  Connecti- 
cut, we  can  find  these  bed-rocks  sometimes,  in  the 
near  vicinity,  but  at  other  times,  not  farther  away 
than  Massachusetts.  In  Ontario,  the  nearest  sources 
of  the  bowlders  are  in  the  regions  east  and  north  of 
Georgian  Bay.  At  Chautauqua,  the  nearest  bed-rock 
for  the  hard  bowlders  is  beyond  Lake  Ontario  and 
Lake  Simcoe.  In  Michigan,  the  nearest  source  is 
north  of  Lake  Huron  and  south  of  Lake  Superior. 
So  in  Indiana,  Illinois,  and  the  northwest  generally, 
we  must  go  northward  to  find  rocks  in  place  which 
are  of  the  same  sorts  as  the  bowlders.  This  is  plainly 
demonstrated  in  the  case  of  bowlders  of  native  copper, 
which  are  frequently  found  in  Wisconsin,  Illinois, 
Indiana,  Michigan,  and  Ohio.  There  is  no  other 
credible  source  than  the  native  copper  region  south  of 
Lake  Superior.  So,  in  the  case  of  the  Pierre  a  hot, 


The  Gravel  Pit.  17 


near  Neufchatel,  the  nearest  credible  source  is  the 
Mont  Blanc  chain  of  Alps,  seventy  miles  distant, 
and  separated  by  the  valley  of  Switzerland  and  the 
Lake  of  Geneva. 

We  seem  authorized  to  conclude,  therefore,  that  the  Generally 
bowlders  have  been  transported  generally  from  the 
north  ;  that  many  of  them  have  been  moved  one  or 
two  hundred  miles  ;  that  they  have  sometimes  been 
borne  over  regions  which  are  now  lake  basins ;  that 
they  have  been  carried,  at  times,  to  higher  levels 
than  their  origin,  and  much  higher  than  valleys  over 
which  they  passed;  that  a  vast  mass  of  sand, 
gravel,  and  clay  was  moved  with  them,  since  they 
lie  imbedded  in  these  accumulations,  to  the  depth, 
sometimes,  of  one  or  two  hundred  feet. 


III. — THE  GRAVEL  PIT. 

ARRANGEMENT  OP  THE    DRIFT. 

THIS  subject  has  its  alphabet,  like  most  others ;  and  Drift, 
every  child  can  testify  that  there  is  little  inspiration 
in  the  alphabet.  A  few  more  letters  of  our  alphabet 
will  be  found  in  the  arrangement  of  the  loose  mate- 
rials which  cover  the  surface  of  the  northern  states. 
These  materials  are  called  Drift.  The  bowlders  are  a 
part  of  the  Drift.  We  wish  to  know  more  about  the 
internal  constitution  of  this  deposit.  Let  us  visit  a 
gravel  pit,  or  some  deep  railroad  cut  through  a  pile  of 
these  incoherent  materials. 

Do  you  find  these  loose  sands  and  gravels  arranged 
in  regular  courses  ?    Yes,  you  say  ;  and  then  you  hes- 


18       Walks  and  Talks  in  the  Geological  Field. 

Structure  ^te »  an(*  we^  vou  mav »  for  *ne  sernblance  of 
of  the  courses  is  exceedingly  interrupted.  Here  is,  indeed, 
Dnft'  a  layer  or  bed,  or  stratum  of  sand,  but  it  thins  out  in 
one  direction,  and  in  the  other  loses  its  upper  and 
lower  boundaries,  and  merges  in  a  general  mass  of 
sand.  Here  is  a  bed  of  gravel,  but  it  lies  at  a  differ- 
ent inclination  from  the  last,  and  in  one  direction  it 
changes  to  sand,  while  in  the  other,  it  becomes  split 
up  into  a  number  of  subordinate  layers  which  bend 
down  and  lose  themselves.  This  bed  also  is  com- 
posed of  many  oblique  laminae,  coarser  and  finer  in 
alternation,  which  are  cut  off  completely  by  the 
upper  and  lower  surfaces  of  the  bed  or  stratum. 
What  is  singular,  the  very  next  bed  below  this, 
which  is  also  obliquely  laminated,  has  its  laminae 
tilted  in  the  opposite  direction.  And  then  next  to 
this  is  a  long  straight  course  of  cobble-stones  and 
pebbles. 

Variety  of  In  some  places  are  large  beds  of  fine  sand,  which 
Drift  ma-  are  taken  out  and  used  for  mortar-making.  In  others 
we  find  extensive  deposits  of  gravel  and  pebbles, 
which  are  used  for  paths  and  streets.  Mixed  in  the 
sands  are  some  cobble-stones  and  large  bowlders. 
Here  and  there,  too,  are  some  beds  containing  much 
clay ;  and  these  are  impervious  to  water.  Now,  all 
this  is  not  a  regular  nor  a  perfect  bedding  or  stratifi- 
cation. We  may  say  the  Drift  here  is  semi-stratified. 
You  can  all  recall  some  locality  where  this  arrange- 
ment of  materials  occurs. 

Upper  and  This  cut  or  exposure,  however,  extends  only  fifteen 
or  twenty  feet  down.  How  is  the  arrangement  be- 
low? There  are  places  where  the  bed-rock  is  not 
reached  in  less  than  a  hundred  or  two  hundred  feet. 


The  Gravel  Pit.  19 


There  are  wells  fifty  to  eighty  feet  deep,  without 
reaching  bed-rock.  Those  who  have  seen  such  wells 
have  observed  the  deeper  structure  of  the  Drift ;  and 
they  report  it  much  like  what  we  see  in  the  gravel- 
pit.  I  will  tell  you  how  we  shall  ascertain  the  ar- 
rangement to  the  depth  of  perhaps  two  hundred  feet. 
Go  to  the  lake-shore,  or  the  sea-shore.  Of  course  it 
must  be  a  place  where  the  shore  is  not  formed  of  bed- 
rocks. Here  the  whole  thickness  of  the  Drift  may 
be  cut  through,  exposing  at  the  bottom  the  solid 
foundation  on  which  the  Drift  reposes.  Well,  here 
we  find  two  kinds  of  Drift.  The  semi-stratified  Drift 
passes  down  into  a  sheet  of  Drift  quite  unstratified. 
It  consists  of  blue  clay  and  a  large  quantity  of  im- 
bedded bowlders.  These  are  rounded  like  those  at 
the  surface.  They  are  in  every  respect  the  same  Tiiior 
thing — made,  apparently,  by  the  same  agency  ;  trans-  Bowlder 
ported  in  the  same  company.  This  is  the  Bowlder 
Clay  or  Till. 

We  must  state,  however,  that  in  some  situations 
the  semi-stratified  Drift  rests  directly  on  the  bed- 
rock. Perhaps  in  these  places  the  Bowlder  Clay  was  Both 

washed  off  before  the  semi-stratified  Drift  was  laid  members 

of  the 
down.     Again,  there   are   many  places  where  the  Drift  not 

semi-stratified  Drift  does  not  rest  on  the  Bowlder  always 

present. 
Clay— perhaps  because  it  was  never  laid  down  ;  but 

more  probably  because  it  has  been  removed.  In  such 
places  the  stiff,  blue  clay  is  exposed  over  the  surface, 
and  the  soil  is  full  of  bowlders.  Can  you  not  call  to 
mind  such  a  place  ? 

The  sheets  of  sand  and  gravel,  often  obliquely  lam- 
inated, which  we  saw  in  the  gravel-pit,  were  there 
cut  through  in  a  vertical  section  presented  edgewise. 


20       Walks  and  Talks  in  the  Geological  Meld. 

You  must  think  of  these  sheets  as  extending  into  the 
earth  a  certain  distance,  but  very  irregular  in  extent 
as  well  as  in  form  and  position.  Some  of  them  are 
flat ;  some  are  concave  upwards,  and  some  are  con- 
vex. Now  and  then  one  is  nearly  horizontal,  but 
most  are  considerably  inclined, 
stratified  Did  you  ever  see  a  huge  mound  of  rock-rubbish  at 

Drift struc-thefootof  a  torrent  rushing  down  a  steep  ravine  to 
ture  due  to 

moving     the  open,  level  land— a  torrent  sometimes  suddenly 
water.        swollen  to  a  terrific  and  maddened  volume,  which 
tears  stones  and  trees  from  their  fastenings?    And 
have  you  ever  seen  such  mound  cut  through  for  a 
highway  or  other  purpose  ?    If  you  have,  you  have 
witnessed  a  semi-stratified  order  of  deposition  some- 
what like  that  in  the  Drift.    Those  who  have  thought 
on  this  resemblance  have  reached  the  conclusion  that 
the  semi-stratified  Drift  must  have  been  moved  and 
laid  down  by  some  kind  of  torrential  action, 
Unstrati-       But  however  this  was,  the  origin  of  the  bed  of 
fled  Drift   Bowlder  Clay  must  have  been  very  different.    Here 
not  due  to  *8  no  sor^  °f  bedding.    The  whole  is  in  a  state  of  uni- 
water.        form  confusion.     Evidently,  then,  Nature  employed 
two  kinds  of  action  successively  in  transporting  and 
dispersing  the  Drift.     In  the  semi-stratified  Drift, 
water  in  tumultuous  movement  may  have  been  the 
chief  agent.    In  the  Bowlder  Drift  water  was  not  the 
chief  agent,  since  here  is  none  of  the  assortment  and 
stratification  due  to  water,  and  here  also  are  rock- 
masses  moved  scores  or  hundreds  of  miles,  and  these 
results  are  not  ascribable  to  water. 

Let  us  take  another  glance  over  the  general  distri- 
bution of  the  Drift.  We  have  seen  the  bowlders  in- 
creasing in  bulk  and  abundance  northward.  We  have 


The  Gravel  Pit.  21 


seen  the  whole  Drift  formation  terminating  south-  The  Drift 

ward  on  about  the  parallel  of  Cincinnati.    We  find  a  north- 

ern  phe- 
incoherent  surface  deposits  in  Kentucky  and  south-  nomenon. 

ward  ;  but  they  contain  no  bowlders  ;  and  they  have 
mostly  resulted  from  the  disintegration  and  decay  of 
the  bed-rocks  in  place.  The  Drift,  then,  is  a  northern 
phenomenon. 

If  we  notice  more  carefully  the  detailed  distribu-  Bowlders 
tion  of  bowlders,  we  find   that,  while  they    have  ^eeled 
generally  moved  southward,  there  has  also  been  a  south- 
radial  distribution  from  high  mountains.     In  New  ward> 
Hampshire  the  bowlders  move  east  and  west  from 
the  White  Mountains,  as  well  as  south.    In  Switzer- 
land,   the    Pierre   d,    bot   and    thousands    of  other 
bowlders    moved    north-westward    from    the    Mont 
Blanc  range  —  though  on  the  opposite  sides  of  Mont 
Blanc  the  movement  was  in  the  opposite  direction. 
In  the  Kocky  Mountains  and  the  Sierra  Nevada,  the 
movement  of  the  bowlders  was  east  and  west  from 
the  mountain  axis.     So,  too,  the  southward  distribu- 
tion of  bowlders  was  greatest  along  mountain  eleva- 
tions. 

Thus  the  distribution  of  Drift  materials  sustains  a  The  re. 
relation  to  altitude  similar  to  that  which  it  sustains  lation  of 
to  latitude.    What  factor,  or  force,  or  agency  exists 


in    altitude  which  exists    identically    in   latitude?  distribu- 

tion of 
Temperature,   certainly.     To  ascend  a  high  moun-  Drlft 

tain  range  is  the  same  as  to  ascend  to  a  high  lati- 
tude. All  high  mountains  support  animals  and 
plants  related  to  species  farther  north.  Ascending 
the  Andes,  you  have  tropical  products  at  the  foot, 
temperate  products  at  ten  thousand  feet,  and  arctic 
conditions  at  the  summit.  The  distribution  of  the 


22       Walks  and  Talks  in  the  Geological  Field. 

Drift,  then,  has  relation  to  heat  and  cold.     Greater 
cold  has  been  accompanied  by  larger  results. 

Now,  how  does  cold  act  to  effect  transportation 
of  rock-fragments  ?  Our  thoughts  run  over  the  world 
to  scrutinize  the  modes  of  action  of  cold.  Much  cold 
implies  much  snow  and  ice,  if  moisture  and  water 
are  abundant.  Most  far  northern  regions  and  high 
mountain  summits  are  covered  much  of  the  year, 
or  the  whole  of  it,  by  a  sheet  of  snow.  Winter  snow, 
under  the  action  of  thawing  and  freezing  tempera- 
tures in  alternation,  becomes  granular,  as  we  often 
observe  in  old  snow,  especially  in  early  spring.  With 
a  more  advanced  stage  of  granulation,  the  icy  grains 
coalesce  into  larger  grains,  and  finally  merge  com- 
pletely into  a  solid  mass  of  ice.  This,  also,  we -have 
often  noticed  in  the  last  lingering  patches  of  last 
winter's  snow. 

Glacier  We  have  many  observations  of  this  kind  on  a  large 
formation.  SCale.  On  high  mountains  broad  fields  of  granular 
snow  come  into  existence,  and  at  a  certain  elevation 
the  average  annual  temperature  is  not  sufficient  to 
dissolve  it  before  autumnal  snows  begin  to  increase 
the  amount.  The  old  snow  becomes  a  permanent 
granular  sheet  on  the  high  slopes.  In  the  Alps  the 
Germans  designate  it  Pirn,  and  the  French,  Neve. 
When  the  firn-masses  are  accumulated  in  valleys,  the 
amount  of  snow  is  so  great  that  it  may  reach  to  a 
much  lower  altitude  before  finding  a  temperature 
which  will  suffice  to  melt  it  all  away  before  the 
next  winter.  So  tongues  of  granular  snow  stretch 
down  the  mountain  valleys,  and  being,  like  our  late 
spring  snow,  exposed  to  increased  action  of  warmth, 
these  valley  prolongations  of  the  upper  firn  become 


The  Gravel  Pit. 


completely  changed  into  solid  ice.      This  is  now  a 
glacier. 

All  substances  expand  with  increase  of  tempera-  Move- 
ture,  and  contract  with  reduction  of  temperature.  ™entof 
The  glacier  is  certainly  at  a  lower  temperature  in 
winter  than  in  summer  —  though  it  can  never  be 
warmed  above  thirty-two  degrees  Fahrenheit,  which 
is  the  thawing  temperature.  The  surface  of  the 
glacier  is  also  at  a  lower  temperature  during  the 
night  than  during  the  day.  The  glacier,  therefore, 
must  sometimes  expand  and  sometimes  contract. 
Now,  when  it  expands,  the  whole  expansion  will  be 
developed  at  the  free  lower  border,  since  the  upper 
border  is  frozen  to  the  earth,  and  pressed  also,  by  the 
snows  beyond.  Also,  if  both  were  free,  most  of  the 
expansion  would  be  developed  below,  because  gravity 
aids  motion  downwards.  Next,  when  the  glacier 
contracts,  the  lower  border  does  not  retreat,  because 
the  ice  is  not  strong  enough  to  bear  the  pull  of  the 
mass  up  the  slope.  The  ice  breaks  in  innumerable 
little  cracks.  These  are  soon  filled  with  water,  which 
freezes,  and  thus  restores  the  complete  solidity  of  the 
glacier.  Thus,  when  the  next  expansion  takes  place, 
the  glacier  takes  another  slide  down  the  valley.  So 
the  glacier  travels.  So,  if  a  whole  state  should  be- 
come glacier-covered,  the  ice-sheet  would  have  a 
motion  from  higher  to  lower,  and  from  colder  to 
warmer.  Every  thing  on  its  surface  would  be  trans- 
ported ;  every  loose  object  beneath  it  or  in  front  of 
it  would  be  pushed  forward. 

Now,  here  are  some  hints  toward  an  explanation  of 
the  method  of  transportation  of  our  millions  of 
bowlders.  If  we  go  to  the  Alps  we  find  exactly  such 


24       Walks  and  Talks  in  the  Geological  Meld. 

Thegia-     glaciers,  on  a  small  scale,  performing  precisely  such 

cier  is  the  work>    Tuus  our  theory  receives  confirmation.    We 

agent  of 

bowlder     can  not  pretend  that  glacier  action  explains  all  the 

trans-  phenomena  of  the  Drift.  The  action  which  arranged 
the  semi-stratified  Drift  must  have  been  exerted  by 
water  rather  than  ice.  But  we  leave  the  subject  now 
to  your  thoughts.  By  and  by  we  shall  come  upon 
this  subject  again  from  another  direction.  (Talk 
XLVII.) 


IV.     AMONG  THE  GLACIEKS. 

GEOLOGICAL   ACTION  OF  GLACIERS. 

PERHAPS  it  is  best  to  pause  at  once  and  contem- 
plate a  fuller  sketch  of  some  living  glaciers.  We  in- 
dulged in  a  little  speculation  about  the  cause  of  the 
Drift.  We  argued  that  glaciers  must  perform  a  work 
pretty  nearly  such  as  the  Drift  required  ;  and  I  cited 
you  to  Alpine  glaciers  as  actually  exemplifying  this 
kind  of  work.  But  come,  now,  let  us  take  a  closer 
look  at  Alpine  glaciers. 

The  vale        About  fifty  miles  from  Geneva  lies  the  "vale  of 
°^cha^  Chamonix"—  the  classic  valley  of  classic  glaciers. 

nix  and  its 

glaciers.  Its  axis  lies  nearly  east  and  west,  and  the  Arve,  tak- 
ing its  rise  from  the  east,  flows  through  the  length  of 
the  valley,  and  bends  north  to  the  Lake  of  Geneva. 
On  the  north,  the  valley  is  bounded  by  the  sharp 
pinnacled  Aiguilles  Rouges  (A-ghee-Roosj) ;  on  the 
south  rises  the  stupendous  mass  of  the  Mont  Blanc 
(Blahnc)  range,  nearly  sixteen  thousand  feet  above 
sea  level.  The  rounded  summit  of  the  monarch 


Among  the  Glaciers.  25 

mountain  is  silver  white  with  perpetual  snow.  On 
one  shoulder  rises  the  Dome  du  Gouter,  and  beyond 
this,  the  Aiguille  de  Gouter,  (A-ghee-du-go6-tay). 
For  three  thousand  feet  below  the  summit,  compact 
snow  covers  the  surface  to  an  unknown  depth.  In 
one  region  below  the  Aiguille  de  Gouter,  may  be  seen 
a  long  perpendicular  cliff  of  snow  left  by  a  slide.  It 
looks  like  a  vast  entablature  to  the  glittering  dome. 
This  is  said  to  be  fifteen  hundred  feet  in  height.  At 
the  foot  of  the  final  dome  stretches  a  fathomless  cre- 
vasse, in  which  a  number  of  persons  have  been  lost. 
This  is  the  "Grande  Crevasse,"  and  for  a  long  time  it 
prevented  all  successful  approach  to  the  mountain's 
summit.  Sometimes  a  temporary  bridge  is  stretched 
across  by  drifting  snow.  Occasionally  it  becomes 
sufficiently  solid  to  serve  for  a  passage  over,  but  it  is 
always  treacherous. 

From  the  Grande  Crevasse  stretches  a  gentle  slope  Features 
called  the  Grand  Plateau  at  an  elevation  of  thirteen 
thousand  feet.  This  is  covered  with  granular  neve. 
Along  its  lower  limit  the  snow-mass  is  broken  into 
tumultuous  confusion,  and  the  passage  over  it  is  diffi- 
cult and  dangerous.  Below  this  is  the  Little  Plateau, 
ten  thousand  feet  above  sea-level;  and  then  come 
other  broken  belts  of  snowy  precipices.  Now,  the 
upper  limits  of  two  glaciers  are  reached  in  the  down- 
ward flow  of  the  ice.  This  common  ice-field  is  a  scene 
of  grand  confusion.  The  mountain  slope  beneath  the 
ice-sheet  .presents  many  irregularities  of  pitch,  and 
many  projecting  bosses.  Over  all  these  the  ice- 
stream  flows  toward  the  lower  level.  In  one  place, 
nine  thousand  feet  above  sea-level,  a  vast  pinnacled 
mass  of  rock  rises  some  hundreds  of  feet  above  the 


26        Walks  and  Talks  in  the  Geological  Field. 

ice.  This  divides  the  wide  stream,  but  the  parts  com- 
pletely coalesce  again  around  the  lower  side.  In 
other  places,  the  underlying  inequalities  break  the 
sheet  by  fractures  large  and  small.  Some  of  these 
crevasses  extend  up  the  general  slope,  and  others  are 
transverse.  The  ice-mass  is  therefore  broken  into 
innumerable  prismatic  fragments.  The  tremendous 
mashing  together  which  they  experience  through  the 
movements  of  the  flow,  squeeze  numbers  of  them  out 
of  their  places  ;  and  they  stand  as  huge  pyramids 
and  columns  ten,  twenty,  and  forty  feet  above  the 
general  surface.  The  columnar  forms  are  called 
sSracs.  The  afternoon  sun  acts  on  them,  and  some 
are  sharpened  to  a  point ;  others  are  worked  out  at 
the  sides,  and  stand  with  broad  flat  caps.  Finally 
they  tumble  down  or  waste  away,  while  new  ones 
rise  in  other  places.  Though  the  ice  is  continually 
shattered  by  crevassing,  the  fissures  are  continually 
closing  together,  when  changes  in  underlying  con- 
figuration permit.  Two  fractured  surfaces  pressed 
tightly  unite  again  as  one  mass ;  and  a  patch  shivered 
into  ten  thousand  fragments  becomes  solid  and  trans- 
parent under  the  lateral  squeezing  to  which  it  may 
become  subjected.  So,  to  whatever  extent  the  ice- 
sheet  may  be  shattered,  it  is  continually  healing,  and 
tends  to  return  to  the  condition  of  a  sound  and  solid 
mass.  Thus  the  tourist,  picking  his  way  among  the 
s6racs,  and  jumping  the  bottomless  chasms,  hears 
frequently  the  detonation  of  some  new  split,  which  is 
echoed  back  from  the  red  pinnacles  of  Mont  Maudit, 
which  rises  on  his  left.  These  themselves  hurl  down 
rocky  fragments  to  keep  alive  the  watchfulness  of 
the  traveler,  and  place  material  on  the  back  of  the 


Among  the  Glaciers.  27 

glacier  to  be  borne  gradually  but  steadily  down  to- 
ward the  valley. 

The  common  glacier-field  just  mentioned  strikes 
the  sharp  upper  limit  of  a  mountain  salience,  which 
slopes  down  to  the  valley  of  Chamonix,  and  separates 
two  mountain  valleys.  This  prominent  dividing 
point  is  the  Aiguille  de  la  Tour.  As  the  common  ice- 
mass  impinges  against  it,  the  ice  parts  to  the  right 
and  left  like  a  river.  Down  the  western  valley  flows 
the  ice-stream  known  as  the  Glacier  de  Taconnay. 
Down  the  eastern  valley  flows  the  greater  stream 
known  as  the  Glacier  des  Bossons,  having  the  little 
village  of  Bossons  at  its  foot.  Another  valley  lies 
still  farther  west,  and  the  common  ice-field  of  Mont 
Blanc  fills  it  with  a  stream  known  as  Glacier  de  la 
Gria. 

These  three  glaciers  descend  to  the  valley  on  the 
west  of  the  pretty  village  of  Chamonix.  On  the 
east  are  three  others.  The  nearest  is  the  celebrated 
Mer  de  Glace,  the  lower  part  of  which  is  called  the 
Glacier  des  Bois,  with  the  little  village  of  Bois  at  its 
foot.  The  snowy  eastern  slope  of  Mont  Blanc  and 
Mont  Maudit  (Mo-de6)  feeds  an  enormous  glacier 
which,  to  an  observer  from  the  valley  of  Chamonix, 
lies  behind  the  pinnacled  summits  of  Charmoz  and 
Midi.  This  is  the  Glacier  du  Geant,  and  it  forms  the 
western  tributary  of  the  Mer  de  Glace.  Into  the 
head  of  the  Mer  de  Glace  comes  the  Glacier  de 
Le~cb.au  d  (La-sh6),  fed  by  the  snow-fields  of  the 
Grandes  Jorasses.  On  the  east,  the  Lfichaud  is  re- 
inforced by  the  broad  triangular  Glacier  de  Talefre 
(Tah-lefr')  in  the  midst  of  which,  at  an  elevation  of 
9,143  feet,  is  the  Jardin,  an  island  of  land-surface, 


28        Walks  and  Talks  in  the  Geological  Field. 

walled  in  on  all  sides  by  lofty  mountains,  and 
adorned  in  August  with  a  display  of  several  species 
of  Alpine  flowers.  Beyond  the  Mer  de  Glace  is  the 
Glacier  of  Argentiere — a  fine  long  river  of  ice,  almost 
equal  to  the  Mer  de  Glace  itself.  The  bright  village 
of  Argentiere  lies  at  its  foot.  At  the  very  head  of 
the  valley  of  Chamonix  comes  down  from  the  same 
direction,  the  Glacier  du  Tour. 
The  seen-  Thus  six  glaciers  descend  into  the  valley,  and  each 

ery  of  the  con^ributes  its  torrent  of  muddy  water  to  create  and 

vale  of 

Chamo-     swell  the  Arve.    This  grand  series  of  ice-rivers  and 

the  more  majestic  mass  of  the  mountains,  with  their 
swelling  domes  and  sky-piercing  pinnacles,  may  be 
contemplated  as  a  panorama  from  the  summits 
which  overlook  the  valley  from  the  north,  and  put 
the  spectator  face  to  face  before  the  stupendous  Mont 
Blanc  range.  No  person  can  gaze  on  this  spectacle 
from  the  F16gere,  which  faces  the  Mer  de  Glace,  or 
from  the  Br6vent,  which  faces  directly  the  Glacier 
des  Bossons  and  Mont  Blanc,  without  feeling  a  sym- 
pathy with  Coleridge  in  his  "  Hymn  in  the  Vale  of 
Chamonix"  : 

Coleridge's  "  Ye  ice-falls !  ye  that  from  the  mountain's  brow 
hymn.  Adown  enormous  ravines  slope  amain, 

Torrents,  methinks,  that  heard  a  mighty  voice, 
And  stopped  at  once  amid  their  maddened  plunge ! 
Motionless  torrents !  silent  cataracts ! 
Who  made  you  glorious  as  the  gates  of  heaven 
Beneath  the  keen  full  moon  ?    Who  bade  the  sun 
Clothe  you  with  rainbow?    Who  with  living  flowers 
Of  loveliest  blue  spread  garlands  at  your  feet  ? 
God !    Let  the  torrents  like  a  shout  of  nations 
Answer,  and  let  the  ice-plains  echo,  God !  " 

The  conception  of  a  glacier  as  a  frozen  cataract  is 
suggestive  and  truthful.    When,  from  the  Montan- 


Among  the  Glaciers.  29 

vert,  overlooking  the  Mer  de  Glace,  De  Saussure  con-  DeSaus- 

templated  the  sea  of  ice,  he  received  an  impression  sure's  de~ 

scription. 
thus  recorded  :    "Its  surface  resembles  that  of  a  sea 

which  has  become  suddenly  frozen — not  during  a 
tempest,  but  at  the  instant  when  the  wind  has  sub- 
sided, and  the  waves,  although  very  high,  have  be- 
come blunted  and  rounded.  These  great  waves  are 
nearly  parallel  to  the  length  of  the  glacier,  and  inter- 
sected by  transverse  crevasses,  the  interior  of  which 
appears  blue,  while  the  ice  is  white  on  its  external 
surface."  Farther  down,  in  the  narrow  Glacier  des 
Bois,  the  sfiracs  and  needles  bristle  over  the  surface 
in  mighty  uplifts  and  fearful  confusion. 

The  crevasses  really  run  in  any  direction,  accord-  crevasses. 
ing  to  the  nature  of  the  underlying  surface.  In 
length  they  vary  from  twenty  feet  to  a  mile.  The 
downward  direction  is  originally  vertical,  but  as  the 
surface  of  the  glacier  moves  more  rapidly  than  the 
deeper  portions,  the  transverse  crevasse  assumes, 
after  a  while,  an  inclination  which  gives  it  a  dip  up 
the  valley.  Its  depth  may  be  ten  or  a  hundred,  or 
two  hundred  feet ;  and  its  width,  which  is  a  few 
inches  at  first,  may  grow  to  fathoms.  Forbes  meas- 
ured a  crevasse  at  the  base  of  the  Glacier  du  G6ant, 
which  had  a  breadth  of  not  less  than  1,214  feet.  The 
two  walls  generally  approach  each  other  downward, 
and  we  may  sometimes  safely  descend  to  the  bottom. 
The  wall-ice  is  absolutely  immaculate,  with  a  green- 
ish blue  transparency.  Down  in  the  crevasse  we 
hear  the  rills  coursing  through  the  substance  of  the 
glacier,  and  sometimes  the  central  torrent  rumbling 
along  the  bottom.  The  surface  of  the  glacier  is  white 
and  granular,  from  the  action  of  the  sun.  Pools  of 


30       Walks  and  Talks  in  the  Geological  Field. 

water  rest  here  and  there — pure,  cool,  arid  refreshing 
— and  numerous  rills  flow  over  the  surface,  discharg- 
ing themselves  through  crevasses  and  perforations  in 
the  ice-mass,  into  some  subglacial  stream. 

Lateral  Each  of  these  great  glaciers  is  bordered  by  a  mo- 
moraines.  raine,  or  long  ridge  of  material  thrown  off  the  sur- 
face in  the  course  of  ages,  and  pushed  up  by  the 
movements  of  the  ice.  It  consists  of  clay  and 
rounded  bowlders.  It  is  completely  unstratifled,  and 
resembles  precisely,  the  till  at  the  bottom  of  the 
Drift.  These  lateral  moraines  at  the  present  epoch, 
tower  fifty  to  eighty  feet  above  their  glaciers.  The 
ice,  for  centuries,  has  been  in  process  of  shrinkage. 
Such  masses  of  d&bris  could  never  have  been  raised 
by  the  existing  glaciers.  Other  attestation  of  a  for- 
mer higher  stage  of  the  glaciers  is  seen  in  the 
smoothed  and  striated  rock-slopes  which  bound  the 
glacier  valleys.  These  surfaces  remind  us  of  the 
smoothed  and  striated  rocks  underneath  the  till  in 
America.  The  records  of  the  glaciers  may  be  traced 
on  these  smooth  slopes,  two  or  three  hundred  feet 
above  the  present  ice-surfaces. 

Terminal  -^  ^ne  ^°°^  °^  eacn  glacier  is  a  terminal  moraine, 
moraines,  which  is  continuous  with  the  two  lateral  moraines. 
Among  the  Chamonix  glaciers,  this  moraine  is  half  a 
mile  or  more  below  the  termination  of  the  ice,  show- 
ing to  what  extent  the  glaciers  have  diminished  in 
length.  These  remote  moraines  were  left  in  1817 
and  1826.  The  "chief  of  guides"  at  Chamonix  re- 
members the  occasion,  and  narrated  to  me  a  number 
of  memorable  incidents.  The  plain  between  the 
moraine  and  the  foot  of  the  glacier  is  strewn  with 
bowlders.  Many  descend  on  the  surface  of  the  ice  or 


Among  the  Glaciers.  31 

imbedded  in  its  mass.  One  sees  them  frequently  pre- 
cipitated from  the  foot  of  the  Glacier  des  Bois  to  the 
plain  below.  The  diminution  of  the  glaciers  appears 
to  be  a  persistent  phenomenon,  and  not  dependent 
on  climatic  fluctuations  of  short  period.  There  must 
be  either  a  continuous  diminution  of  cold  or  of  pre- 
cipitation. 
All  parts  of  the  glacier  mass  move  continually  Glacial 

downward.    In  the  Glacier  des  Bossons  the  amount  mov^ 

merit, 
of  the  movement  has  been  determined  by  means  of  a 

catastrophe.  In  1820,  eight  persons  were  buried  in 
the  Grande  Crevasse  at  the  foot  of  the  dome  of  Mont 
Blanc.  In  1861,  their  remains  began  to  appear  in  the 
ice  near  the  termination  of  the  glacier.  In  forty 
years  they  had  traveled  26,000  to  29,000  feet,  or  680 
feet  a  year.  As  they  were  buried  200  feet  beneath  the 
surface,  it  appears  that  200  feet  had  been  melted  from 
the  top  of  the  glacier  in  the  same  interval.  The  Mer 
de  Glace,  as  shown  by  Forbes,  moves  past  Montaii- 
vert  at  the  rate  of  822  feet  per  annum.  Near  the  foot 
of  the  Glacier  des  Bois  the  motion  is  209  feet  a  year. 
The  lower  Glacier  of  the  Aar,  which  was  the  scene 
of  Agassiz's  observations,  moves  downward  at  an 
average  rate  of  250  feet  per  annum.  Hugi's  hut, 
according  to  Agassiz,  had  been  carried  5,900  feet  in 
thirteen  years.  A  record  bottled  up  by  Hugi,  stated 
that  it  had  traveled  197  feet  in  three  years  and  2,345 
feet  in  nine  years.  The  great  continental  glacier 
would  not  have  traveled  at  rates  so  rapid  ;  but  if  it 
moved  200  feet  a  year,  the  time  required  to  transport 
a  bowlder  250  miles  would  be  6,600  years. 

These  interesting  Chamonix  glaciers  are  but  the 
stumps  of  what  they  have  been.    Once  they  were 


32       Walks  and  Talks  in  the  Geological  Meld. 

Alpine       noble  tributaries  of  a  greater  glacier  which  filled  the 

glaciers      valley  of  Chamonix.    Out  of  this  valley  it  passed 

nants        along  the  valley  of  the  Arve,  all  the  way  to  Geneva. 

only.         As  we  ride  along  the  highway,  the  rocky  bounding 

walls  rise  on  either  hand,  smoothed  and  scored  after 

the  same  fashion  as  the  rock-walls  of  the  valley  of  the 

Mer  de  Glace.    Evidently,  the    Chamonix  glaciers 

have  long  been  in  process  of  shrinkage.    Evidently, 

they  once  existed  under  an  enormous  development. 

When  that  period  was  passing,  we  may  well  believe 

our  northern  states  were  extensively  glaciated,  and  a 

work  was  in  progress  very  nearly  like  that  which  we 

have  already  reasoned  out. 


V.    THE  HILLSIDE  SPRING  AND  ITS  WORK. 

SUBTERRANEAN  WATERS  AND    THEIR  DEPOSITS. 

WHERE  goes  the  rain  which  falls  upon  the  earth  ? 
If  the  surface  were  completely  level,  and  all  the 
water  should  stand  which  comes  from  the  clouds  in 
the  form  of  rain  and  snow  in  one  year,  it  would 
be  everywhere  about  forty  inches  deep.  Such  an 
amount  of  water  would  be  34,480  barrels  on  every 
acre.  What  becomes  of  all  that  water  ? 

Part  of  it  runs  off,  you  say  ;  and  part  of  it  soaks  in 
the  ground.  True,  and  part  of  it  evaporates,  and  is 
Rain  water  afterward  condensed  and  rained  down  again.  Also, 
into*11"116  Par*  °^  *nat  wnich  soaks  in  the  ground  returns  when 
ground  the  surface  becomes  dry,  and  is  evaporated.  But,  let 
Jart^oms  us  attemPt  to  follow  the  water  which  soaks  in. 
material.  First  of  all,  it  must  have  dissolved  some  substances 


The  Hillside  Spring  and  its  Work.  33 

with  which  it  came  in  contact  at  the  surface.  These 
substances  must  be,  to  a  limited  extent,  certain  min- 
eral constituents  of  the  Drift ;  but  the  Drift  has  been 
so  many  thousand  years  exposed  to  rains,  that  all  its 
readily  soluble  constituents  have  been  dissolved  away 
from  the  surface.  The  chief  agencies  which  supply 
soluble  matters  to  the  surface  are  man  and  animals. 
The  underground  waters,  therefore,  carry  with  them 
a  certain  amount  of  solutions  of  organic  and  in- 
organic origin,  and  are  not  absolutely  pure,  like  care- 
fully distilled  water.  They  may  even  be  poisonous 
and  unsanitary. 

Following  these  waters  in  thought,  beneath  the  Clay  beds 
surface,  we  see  them  percolating  through  the  sands  arres*  de~ 
and  gravels,  which  we  have  found  to  make  up  the  water, 
principal  part  of  the  upper  Drift.    Through  layer 
after  layer  they  continue  to  descend.    If  any  ob- 
struction is  encountered,  they  are  quickly  deflected 
around  it,  and  so  continue  to  settle  toward  the  imper- 
vious Bowlder  Clay  at  the  botton  of  the  Drift ;  or,  if 
that  is  absent,  the  waters  settle  to  the  bed-rock.    We 
will  not  attempt,  at  present,  to  follow  them  in  the 
rocks. 

Now,  we  know  that  the  Drift  contains  sheets  of 
impervious  clay.  Of  course,  then,  these  intercept  the 
descending  water.  The  water  arrested  by  a  clay-bed 
saturates  the  overlying  sand,  and  gradually  flows 
along  the  surface  of  the  clay  to  a  lower  level.  But 
we  have  seen  that  all  these  Drift  beds  are  of  quite 
limited  extent.  The  water,  therefore,  soon  reaches 
the  edge  of  the  clay-bed  and  escapes  down  to  a  lower 
level.  Probably  it  is  again  intercepted  by  a  deeper 
clay-bed.  Along  this  it  flows  in  a  similar  way,  and 


34       Walks  and  Talks  in  the  Geological  Field. 

so  continues— always  approaching  nearer  and  nearer 
to  the  lower  limit  of  the  Drift.  Some  of  the  clay- 
beds  are  concave  upward,  and  thus  form  real  dishes 
or  cisterns,  which  remain  full. 

Conditions  Suppose  we  dig  a  well.  While  passing  through 
ells'  the  sandy  strata,  from  which  the  water  drains  away, 
no  supply  will  be  struck.  As  soon,  however,  as  we 
reach  one  of  the  subterranean  basins  or  cisterns,  a 
supply  is  found.  Should  we  dig  a  hole  through  the 
bottom  of  the  cistern,  we  would,  of  course,  lose  much 
if  not  all  of  the  water.  But  we  might  continue  down 
to  the  next  water-basin. 

Let  us  suppose  another  well  is  needed,  a  few  rods 
away.  We  must  not  be  too  sanguine  in  the  expecta- 
tion of  getting  water  at  the  same  depth.  Perhaps 
the  new  well  is  beyond  the  limits  of  the  higher  water 
basin  ;  we  must  then  dig  to  some  lower  one.  Perhaps 
the  new  well  is  on  higher  ground  ;  it  does  not  follow 
that  we  must  dig  to  the  level  of  the  basin  in  the  first 
well.  In  the  higher  ground  may  be  a  higher  water- 
basin  ;  and  so  the  second  well,  though  several  feet 
higher  than  the  first,  may  not  require  to  be  so  deep. 

Do  not  suppose  these  water-beds  are  everywhere  of 
such  limited  extent.  There  are  districts  where  the 
same  bed  may  be  traced  one  or  two  miles.  The  bed, 
in  such  cases,  is  nearly  horizontal ;  and  that  condi- 
tion of  the  underground  structure  is  indicated  by  a 
level  condition  of  the  surface. 

Hillside         Now,  how  are  springs  produced  ?    Suppose  a  river 

springs,      valley  has  cut  through  a  deep  mass  of  the  Drift,  must 

it  not  cut  the  water-bearing  sheets  with  the  rest? 

And  when  that  is  done,  will  not  the  water  flow  out? 

Certainly.    The  water  in  escaping  from  the  cut  edge 


The  Hillside  Spring  and  its   Work.  35 

of  the  sheet  finds  some  spot  where  least  resistance  is 
experienced,  and  there  it  escapes  in  largest  quantity. 
It  forms  a  sort  of  stream,  and  by  degrees  wears  a  little 
channel,  which  extends  back  into  the  bank,  opening 
at  its  mouth  in  a  little  arch  under  which  the  water 
finally  escapes.  Of  course,  all  the  work  was  accom- 
plished before  we  ever  saw  the  spring.  A  well  is  an 
artificial  spring. 

Generally,  the  water  of  a  hillside  spring  is  allowed 
to  flow  off  to  a  brook  or  rivulet.  In  the  course  of  a 
number  of  miles,  scores  or  hundreds  of  springs  may 
discharge  their  contributions  into  the  stream.  In 
fact,  the  greater  part  of  the  water  in  the  stream  is  - 
supplied  by  springs.  It  gets  directly  from  rains  only 
so  much  as  flows  from  the  surface  of  the  basin  which 
the  river  drains.  Most  of  the  rain  falling  within  the 
basin,  however,  sinks  into  the  ground,  and  finds  its 
way  into  the  stream  only  in  the  form  of  spring  water. 
But  when  a  stream  flows  over  a  drift-formed  bed, 
much  water  wastes  away.  Besides  this,  many  deep 
water-basins  convey  their  contents  under  the  river. 
So  the  river  never  contains  the  whole  amount  of 
water  which  falls  within  the  basin  which  it  drains. 

Suppose  all  the  water-basins  under  a  township  or  a  Value  of 
county  should  cease  to  exist,  what  would  become  of  8Prines- 
wells  and  springs?    You  understand  at  once   that 
they  would  dry  up.    Therefore  the  streams  would 
dry   up.      The  water  would  settle  to  the  Bowlder 
Clay  or  the  bed-rock,  and  there  would  be  the  only 
accumulation.    Every  well  must  then  be  sunk  to  that 
depth — even  if  it  were  two  hundred  feet.    And  wells 
would  be  the  only  resort,  for  of  springs  there  would 
be  none  ;  of  brooks  there  would  be  none  ;  of  ponds 


36       Walks  and  Talks  in  the  Geological  Field. 

and  lakelets  there  would  be  none.  Then,  again,  the 
Drift  sands  being  so  dry,  little  evaporation  would 
take  place  from  the  earth's  surface.  The  air  would  be 
dry ;  no  dew  would  condense  ;  no  clouds  would  form, 
and  so  the  rains  would  stop  descending,  unless  some 
other  region  could  supply  us  with  clouds.  How 
beneficent,  then,  are  the  clay-beds !  Literally,  they 
are  all  which  saves  many  a  fertile  region  from  be- 
coming a  desert  and  an  uninhabitable  waste. 

In  regions  of  deep  Drift  and  abundant  water- 
basins,  the  supplies  of  spring-water  are  sometimes 
sufficient  to  meet  the  demands  of  towns  and  cities. 
The  city  of  Ann  Arbor,  with  its  ten  thousand  of  pop- 
ulation, is  thus  supplied  with  nearly  five  hundred 
thousand  gallons  daily.  This  is  obtained  from  two 
groups  of  springs,  and  distributed  through  the  city  in 
the  usual  way.  Five  times  this  amount  could  be  had, 
if  needed. 

Solution  of  Now  let  us  consider  springs  in  another  light.  We 
limestone.  have  already  reflected  that  the  percolating  water 
takes  some  substances  in  solution  from  the  surface. 
It  must  take  up  much  more  in  leaching  through  the 
sands.  This  is  the  reason  why  most  sands  are  com- 
posed chiefly  of  insoluble  constituents.  Their  soluble 
constituents  have  been  leached  out.  But  there  re- 
main still,  in  many  regions,  some  soluble  limestone 
pebbles  or  larger  masses  which  have  not  yet  been 
dissolved,  and  the  water  is  continually  diminishing 
the  amount  of  these. 

Water  that  has  dissolved  much  limestone  is 
"hard."  Hence,  many  spring  and  river  waters  are 
hard.  The  water  of  a  pond  may  be  softer,  because 
a  large  proportion  of  it  has  been  directly  rained  in,  or 


KONWAKITON  GLACIER,  MOUNT  SHASTA,  CALIFORNIA. 


146347 


38        Walks  and  Talks  in  the  Geological  Field. 

supplied  by  surface  drainage  from  the  surrounding 
land.  Of  course,  the  hardness  of  underground  water 
depends  upon  the  amount  of  limestone  pebbles  and 
grains  with  which  it  has  come  in  contact.  Aside 
from  any  supply  of  limestone  from  neighboring 
ledges,  the  amount  of  limestone  in  the  Drift  depends 
on  the  amount  transported  from  the  northern  regions 
which  supplied  the  material  of  the  Drift  at  each  par- 
ticular place.  Some  northern  regions  supplied  much 
limestone,  and  others  little.  Hence,  in  Michigan, 
Ohio,  and  Indiana,  well  and  spring  waters  are  hard, 
while  in  New  England  and  Pennsylvania  they  are 
comparatively  soft. 
Deposits  Underground  water  often  experiences  great  pres- 

from          sure.    In  this  state  it  dissolves  more  limestone  than 
springs. 

it  can  hold  in  solution  after  the  pressure  is  relieved. 

Hence  many  springs  throw  down  a  calcareous  de- 
posit which  in  the  open  air  hardens  into  tufa  and 
travertine.  It  often  incrusts  mosses  and  forms  what 
is  called  "petrified  moss."  The  vegetable  matter 
perishes  and  disappears  by  degrees,  but  the  form  of 
the  moss  remains.  Calcareous  springs  flowing  into 
ponds  cause  a  deposit  of  chalky  matter  on  the  bot- 
tom, which  is  called  marl.  It  is  generally  mixed 
with  earthy  substances  washed  in  from  the  surround- 
ing slopes.  In  precisely  the  same  way  certain  springs 
deposit  peroxide  of  iron,  which  is  yellowish  or  red. 
Iron  is  also  often  transported  to  bogs  and  ponds, 
and  there  undergoes  deposition.  Thus  bog  iron  ore 
is  formed. 


Introduction  to  the  Rocks.  39 


VI.     INTRODUCTION  TO  THE  BOCKS. 

KINDS  OF   MINERALS  AND  STONES. 

IT  is  not  entirely  satisfactory  to  roam  over  the 
fields,  with  bowlders  lying  on  the  right  and  left,  but 
without  any  knowledge  of  their  names  or  natures. 
True,  we  shall  experience  much  satisfaction  in  feel- 
ing that  we  know  something  of  their  origin  and 
their  history.  We  may  walk  up  to  the  side  of  one  of 
these  ancient  and  way-worn  travelers  and  say:  "  Old 
Hard  Head,  when  did  you  arrive  in  this  country,  and 
where  did  you  emigrate  from?"  Old  Hard  Head  will 
lie  sullenly  and  answer  never  a  word.  But  he  is 
written  all  over  with  inscriptions  which  we  can 
already  begin  to  decipher.  So  we  look  on  the 
rounded  and  weather-beaten  form,  and  say  to  our- 
selves :  "  This  immigrant  rock  came  from  a  north- 
ern country.  He  left  his  mother-rock,  and  most  of 
his  kindred,  in  the  woods  of  northern  Maine,  or  New 
Hampshire,  or  on  the  shore  of  Lake  Superior.  A 
large  number  of  his  kindred  came  with  him.  He 
rode  part  of  the  way  on  the  back  of  a  glacier.  By 
and  by  he  fell  off,  or  got  into  a  hole  ;  and  after  that 
he  had  a  severe  squeezing.  He  got  crushed  and 
rubbed  and  rolled  and  pushed  for  some  thousands  of 
years.  But.  every  year  he  made  some  progress. 
By  and  by  there  was  a  great  change  of  weather. 
The  ice-carriage  melted  away  from  him,  and  fine 
weather  returned,  and  lo  !  he  found  himself,  one 
spring,  in  this  field." 


40       Walks  and  Talks  in  the  Geological  Field. 


Minerals 
compose 


Quartz 

and 

quartzites. 


To  complete  our  introduction  to  old  Hard  Head  we 
must  know  his  name.  To  call  him  old  Hard  Head  is 
like  calling  a  man  "  Old  Russian  "or  "  Old  English- 
man." He  has,  besides,  his  personal  name.  Now, 
there  is  a  way  of  finding  out  the  particular  name  of 
each  rock.  Like  a  dog  with  his  name  on  his  collar, 
each  mute  rock  displays  a  name  written  on  its  ex- 
terior. Let  us  look  into  this  subject  a  few  minutes. 

Do  you  see  that  nearly  all  these  bowlders  appear  to 
be  mixtures  of  different  colors  and  kinds  of  mate- 
rials ?  See  one  rock  with  round  pebbles — white,  red, 
black— imbedded  in  a  mass  of  smaller  grains.  See 
another  rock,  less  coarse,  with  grains  white,  pink, 
and  black.  See  still  another  with  grains  all  nearly 
alike.  See  one  rock  nearly  a  uniform  white  ;  an- 
other, bluish ;  another,  reddish ;  another,  nearly 
black.  See  one  rock  with  numerous  black  shining 
scales ;  another,  with  smoky  scales ;  another,  with 
silvery  scales.  Now,  all  these  differently  colored 
constituents  of  the  rocks  are  so  many  different  min- 
erals. Rocks  are  composed  of  minerals.  Some  rocks 
have  two  minerals  ;  some,  three  ;  some,  four ;  and 
some,  only  one.  The  particular  name  of  a  rock  de- 
pends on  the  minerals  in  it.  As  soon  as  we  know 
the  minerals,  we  can  call  the  name  of  the  rock. 
Now,  sit  down  and  take  a  lesson  in  minerals. 

Do  you  see  this  white  flint  rock,  composed  through- 
out of  one  kind  of  mineral  ?  That  mineral  is  Quartz. 
It  is  the  hardest  of  all  the  common  minerals.  Try  to 
scratch  it.  You  see  the  point  of  steel  makes  no  im- 
pression on  it.  But  it  leaves  a  black  mark.  The 
quartz  wears  away  the  steel.  When  one  of  these 
bowlders  is  thus  composed  entirely  of  quartz,  its 


Introduction  to  the  Rocks.  41 

name  is  Quartzite.  There  are  many  quartzites.  Let 
us  learn  the  other  part  of  the  name.  Look  at  these 
uniformly  colored  quartzites — white  and  gray.  You 
see  one  is  composed  of  distinct  grains  ;  this  is  a  Gran- 
ular Quartzite.  One  has  the  grains  almost  com- 
pletely melted  together  or  confluent ;  this  is  a  Vitre- 
ous Quartzite.  One  contains  pebbles  ;  this  is  a  Con- 
glomeritic  Quartzite^  or  simply  a  Conglomerate.  An- 
other has  some  of  its  pebbles  red  ;  this  is  a  Jcispery 
Conglomerate.  You  will  find  quartzites  exceedingly 
abundant;  and  you  will  find  grains  of  quartz  in 
many  other  rocks  than  quartzites.  In  fact,  quartz  is 
most  abundant  of  all  minerals. 

Conglomerates  always  excite  curiosity — especially  congiom- 
if  the  pebbles  are  of  different  bright  colors.     Two  erates* 
large  masses  of  conglomerates  of  different  sorts  lie 
on  the  campus  of  the  University  of  Michigan— sou- 
venirs of  two  graduating  classes.    One  is  a  jaspery 
conglomerate  from  the  north  shore  of  Lake  Huron. 
It  weighs  six  tons.    The  plum  pudding,  as  big  as  the 
State  House  dome,  demolished  by  the  giant's  wife 
and  her  screaming  boys,  refers  to  a  conglomerate. 

"  They  flung  it  over  to  Roxbury  hills, 

They  flung  it  over  the  plain ; 
And  all  over  Milton  and  Dorchester,  too ; 
Great  lumps  of  pudding  the  giants  threw  ; 

They  tumbled  as  thick  as  rain." 

Well,  here  is  a  rock  with  shining  scale-like  mineral  Mica, 
fragments.  Pick  up  a  scale  with  your  knife-blade. 
Do  you  see  it  split  into  laminae  or  leaves  of  indefinite 
thinness  ?  "  Yes,"  you  say ;  "  this  is  the  same  thing 
as  is  used  in  the  doors  of  our  stoves  to  permit  the 
light  to  shine  through  ;  only  these  are  black  leaves 


42       Walks  and  Talks  in  the  Geological  Field. 

and  those  are  transparent."  Quite  right.  What  do 
you  call  the  mineral  in  your  stove  door?  "Mica, 
though  some  people  call  it  isinglass."  Mica  is  cor- 
rect. One  species  of  mica  is  black,  and  has  a  partic- 
ular name  ;  another  varies  from  dark-brown  or 
smoky  to  transparent,  and  has  a  different  name. 
There  are  also  some  other  species  of  mica.  So  you 
know  mica. 

Feldspar.  Examine  this  rock  very  closely — do  you  find  any 
quartz?  "Yes,"  you  say,  "there  are  two  kinds  of 
light-colored  minerals  here."  Carefully  test  them 
both  for  hardness.  Can  you  scratch  them  ?  "Well, 
no.  One  of  them  is  hard  enough  for  quartz — it  is 
quartz  ;  but  the  other  I  am  uncertain  about."  Then 
you  must  try  again.  Bear  on  hard  ;  can't  you  make 
a  little  scratch  with  your  knife-point,  or  the  end  of  a 
file?  "  I  believe  I  do  make  a  little  impression  on  it." 
Well,  then,  it  is  not  quartz.  Now  take  another  look 
at  it.  Compare  it  with  the  quartz  grain  by  its  side. 
Is  its  surface  broken  and  irregular?  "No,"  you  say, 
"  it  is  flat."  Hold  it  then  so  as  to  reflect  the  light 
from  the  window.  Is  the  reflection  as  bright  and 
glassy  as  the  reflection  from  the  quartz  ?  "I  think 
there  is  a  little  difference."  You  see,  too,  it  is  an  un- 
broken reflection,  while  that  from  the  quartz  is  not 
uniform,  in  consequence  of  the  uneven  surface. 
There  is  also  another  point ;  this  mineral  appears  to 
be  a  fragment  of  a  crystal ;  you  can  detect  one  or 
more  edges  or  angles.  It  is  not  so  with  the  quartz. 
Thus,  in  several  particulars,  this  mineral  differs  from 
quartz.  Its  name  is  Feldspar.  But  feldspar  is  not 
always  white  nor  cream-colored.  Very  often  it  is 
pink-tinted  ;  often  almost  red.  But  you  may  know 


Introduction  to  the  Rocks.  43 

it  to  be  feldspar  by  the  same  signs,  independently  of 
color. 
So  we  find  in  this  bowlder  three  different  minerals,  Granite, 

and  their  names  are   Quartz,  Mica,  and  Feldspar.  sneiss. 

granulite, 
These  three  minerals  mixed  together  form  the  rock  and  mica 

Granite.  There  are  several  varieties  of  granite,  ac-  scnist- 
cording  to  the  species  of  mica  ;  according  to  the  colors 
of  the  quartz  and  feldspar ;  according  to  coarseness 
of  the  constituents  ;  according  to  the  relative  propor- 
tions of  the  three  ingredients.  But  they  are  all  gran- 
ites. If,  however,  the  minerals  are  not  uniformly 
mixed ;  if  they  are  ranged  in  courses,  the  rock  is 
stratified,  and  it  is  not  a  proper  granite,  though  quar- 
rymen  and  builders  often  call  it  granite.  Properly, 
it  is  Gneiss  (Nice).  If  the  mica  is  almost  or  com- 
pletely wanting  in  a  granite-like  rock,  the  rock  is 
Granulite.  When  a  gneiss-like  rock  contains  very 
little  feldspar,  it  is  Mica  Schist  (Shist). 

Now,  let  us  examine  another  bowlder,  with  a  sim-  Horn. 
ilar  appearance,  but  in  which  the  dark  mineral  is  not  blende, 
mica.    Be  sure,  first  of  all,  that  we  have  quartz  and 
feldspar  in  it.     Then,  if  the  dark  mineral  is  not  born- 
scaly,  it  is  probably  Hornblende.    It  may  be  nearly 
black,  or  greenish-black,  or  dark  green.    It  may  be 
in  grains,  or  in  flat-sided  fragments  showing  an  in- 
distinct fibrous  structure.    It  can  be  scratched,  giv- 
ing a  pale  bluish-green  streak.     Now,  a  rock  with 
these  constituent  minerals — Quartz,   Feldspar,  and 
Hornblende— is  /Syenite,  so  called  because  the  rock 
quarried  by  the  ancient  Egyptians  at  Sye'ne  was  of 
this  kind.    Many  persons  call  this  granite  also.    The 
"  Quincy  granite,"  near  Boston,  is  a  syenite.    Often 
syenite  contains  also  some  mica.    This  is  the  case 


44        Walks  and  Talks  in  the  Geological  Field. 

with  the  "obelisk,"  in  Central  Park,  New  York,  and 
the  Mormon  Temple,  in  Salt  Lake  City.  If  the  con- 
stituent minerals  tend  to  arrangement  in  courses,  the 
rock  is  stratified,  and  we  call  \iSyenitic  Gneiss.  If  the 
quartz  is  wanting,  or  nearly  so,  the  rock  is  Hyposy- 
enite  when  the  feldspar  is  of  the  common  kind,  and 
Diorite  when  otherwise.  When  Syenitic  Gneiss  con- 
tains very  little  feldspar,  we  call  the  rock  Hornblende 
Schist. 

Other  The  names  above  explained  embrace  a  majority  of 

crystalline  ^g  rocks,  and  I  do  not  by  any  means  expect  you  to 
crystalline  learn  at  present  all  of  the  others.  But  we  may  men- 
rocks>  tion  a  few.  Some  rocks  appear  to  be  composed 
wholly  of  one  mineral,  and  yet  they  are  not  quartz- 
ites.  They  are  mostly  dark-colored—slate-colored  or 
blackish  or  greenish.  If  these  are  banded  in  differ- 
ent colors,  or  are  capable  of  splitting  into  sheets,  like 
shingles,  they  are  Arglllites— including  most  of  the 
hard  slates,  like  roofing  slate.  If  a  rock  is  very  fine, 
blackish,  and  harder  than  slate,  it  may  be  an  Apha- 
nite.  If  it  consists  of  a  very  fine,  hard,  uniform  red- 
dish or  greenish  base,  having  crystals  of  feldspar 
scattered  through  it,  the  rock  is  a  Porphyry.  But,  if 
you  feel  inclined  to  go  further  into  rock-details,  it 
will  be  better  to  study  some  work  which  takes  up 
the  subject  more  thoroughly.  (See  the  Author's  Geo- 
logical Excursions,  and  still  fuller  Geological  Studies}. 
Sedimen-  One  word  more.  These  bowlder  rocks  are  all  hard, 
tary  rocks.  cryStalline,  and  generally  (not  always)  foreign  to  the 
region  where  they  lie.  We  sometimes  find  fragments 
of  rocks  which  are  not  hard  and  crystalline,  and  far- 
fetched. They  come  from  ledges  which  appear  at 
the  surface  not  far  away.  The  most  common  uncrys- 


The  Moods  of  the  Great  Lakes.  45 

talline  ledges  are  of  sandstone,  limestone,  and  shale. 
Sandstone  is  composed  chiefly  of  grains  of  quartz — 
like  those  in  a  granular  quartzite,  but  not  so  brilliant 
or  so  firmly  compacted  together.  A  grindstone  is  a 
fine  sandstone.  Limestone  can  be  easily  scratched 
with  a  knife ;  is  generally  not  composed  of  grains ; 
and,  if  you  apply  strong  acid,  an  effervescence  takes 
place.  Very  strong  vinegar  will  often  suffice,  es- 
pecially if  the  rock  is  first  pulverized.  Shale  is  quite 
soft,  easily  cut  with  a  knife,  dark-bluish  or  black, 
splitting  into  thin  sheets.  It  is  exceedingly  common 
in  coal  regions.  It  crumbles  into  small  fragments, 
and  finally  becomes  mere  mud. 

I  think  this  little  knowledge  about  rocks  is  better 
than  total  ignorance.  We  may  now  go  amongst  our 
bowlders,  and  speak  many  of  their  names. 


VII.  THE  FLOODS  OF  THE  GREAT  LAKES. 

LACUSTRINE  DEPOSITS  AND  TERRACES. 

PERSONS  living  along  the  borders  of  the  "Great  The  Ridge 
Lakes"  well  understand  what  is  meant  by  "The  Road- 
Ridge  Road."   That  road  is  a  geological  phenomenon. 
It  is  a  record  of  high  waters  in  the  lakes. 

The  Ridge  Road  runs  parallel  with  the  lake  shore 
for  many  miles  at  a  stretch.  It  is  almost  perfectly 
level  and  serves  as  a  ready  made  road-bed  for  country 
roads.  It  consists  of  gravel  and  sands,  and  presents 
oblique  lamination  or  cross-bedding  in  its  internal 
structure.  The  materials  have  evidently  been  ar- 
ranged by  water.  It  has  the  general  characters  of 


46       Walks  and  Talks  in  the  Geological  Meld. 

a  beach,  and  like  a  beach  retains   a   level   nearly 

uniform.      Generally  two  or  more  of  these  ancient 

Evidence   beaches  run  parallel  with  the  lake,  at  different  alti- 

of former   tudes.     The  "ridge-road"  south  of  Lake  Ontario  is 

higher 

level  of  190  feet  above  the  lake.  The  principal  terrace  border- 
the  Great  ing  Lake  Erie  is  220  feet  above  the  lake  on  the 
south  side.  On  the  north  side,  near  Toronto,  there 
are  terraces  from  30  to  500  feet  above  the  lake.  The 
Davenport  ridge  west  of  Toronto  is  250  to  300  feet. 
At  the  west  of  Lake  Ontario,  near  Dundas,  the  ridge 
is  318  feet  high.  Around  Lake  Huron  are  clayey 
deposits  up  to  500  feet.  North  of  Lake  Superior  the 
upper  terrace  reported  is  331  feet  above  the  lake. 
Evidence  There  are  other  indications  that  the  Great  Lakes 
from  have  formerly  stood  much  higher  than  at  present. 
Island  Mackinac  Island  is  a  monument  commemorating 
in  stone  the  fact  of  the  ancient  high  tides  of  the 
lakes.  Get  into  a  Mackinac  boat  and  sail  around  the 
island.  On  all  sides  a  wall  of  limestone  rises  perpen- 
dicularly from  the  water's  edge  to  a  height  of  about 
150  feet.  Only  on  the  south,  for  a  narrow  space, 
is  the  approach  practicable.  Here  is  the  village ; 
back  of  it,  on  the  first  rock-terrace,  is  the  modern 
fort.  The  old  Fort  Holmes,  captured  by  the  British, 
is  on  the  highest  dome  of  the  island,  350  feet  above 
the  lake.  As  we  pass  along  the  limestone  wall  which 
bounds  the  island,  we  see  the  waves  breaking  against 
the  barrier.  We  notice  the  peculiar  smooth  con- 
cavities into  which  they  wore  the  exposed  surface. 
These  are  marks  characteristic  of  wave  action.  Our 
eyes  follow  along  the  weathered  buttresses  to  the 
summit.  From  bottom  to  top  are  the  same  records  of 
warring  waves.  There  was  evidently  a  time  when 


The  Floods  of  the  Great  Lakes.  47 

the  lake  acted  at  the  height  of  150  feet  precisely  as  it 
acts  to-day  at  the  lake-level,  before  our  eyes.  We 
ascend  to  the  main  plateau  of  the  island.  On  this 
rises  a  striking  monument-like  remnant  of  a  forma- 
tion which  once  covered  the  whole  of  this  plateau  to 
an  altitude  at  least  134  feet  greater.  This  is  "  Sugar 
Loaf."  But  notice  the  fashion  of  its  sides.  Here, 
too,  are  the  same  smooth  conchoidal  depressions  as 
the  lake  is  still  carving  in  the  wall  at  the  water's 
edge.  The  waves  have  certainly  been  there.  The 
time  was  when  Lakes  Huron  and  Michigan  stood  at 
least  200  feet  higher  than  at  present. 

Think  of  that  condition  of  things.  Picture  the  Great 
lakes  filled  up  till  the  water  covered  Sugar  Loaf.  J^6®** 
At  present,  Lake  Superior  stands  twenty  feet  higher  high  level, 
than  Lakes  Michigan  and  Huron.  These  are  sixteen 
feet  higher  than  Lake  Erie ;  and  the  descent  thence 
to  Lake  Ontario  is  323  feet.  This  is  according  to  Gan- 
nett. Now,  we  find  lake-terraces  up  to  three,  four 
and  five  hundred  feet  above  the  present  levels  of  the 
lakes.  But  let  us  assume  the  principal  terrace  south 
of  Lake  Erie  as  representing  the  highest  flood  of  the 
lakes.  This  220  feet  above  Lake  Erie,  204  feet  above 
Lakes  Huron  and  Michigan,  and  180  feet  higher  than 
Lake  Superior.  We  have  perfectly  satisfactory  proof 
that  the  water  of  the  Great  Lakes  has  stood  at  least 
as  high  as  this.  Now  let  us  cast  our  eyes  over  the 
expanse.  The  sites  of  all  the  busy  and  populous  lake 
cities  are  submerged.  The  greater  part  of  the  penin- 
sula of  Ontario  is  under  water.  The  flood  stretches 
westward  of  Detroit  twenty-seven  miles.  There,  near 
Ypsilanti  is  the  ancient  beach  which  marks  the  limit 
of  the  flood.  Mackinac  Island  is  submerged  to  the 


48        Walks  and  Talks  in  the  Geological  Meld. 

pinnacle  of  Sugar  Loaf.  Passing  around  to  the  head 
of  Lake  Michigan,  we  find  the  vast  inland  sea 
stretching  southward  and  westward  over  a  large  part 
of  the  state  of  Illinois. 

No  bar-  What  hemmed  in  this  broad  expanse  of  water 
riers  on  tne  gou^n  ?  r^his  interesting  question  has  not 
been  completely  answered.  We  know  that  in  south- 
ern Illinois  are  the  remains  of  an  ancient  barrier 
which  crossed  the  Mississippi,  and  was  worn  down 
for  the  passage  of  the  great  river.  The  barrier  is 
a  prolongation  of  the  Ozark  range,  from  Missouri. 
The  gap  cut  through  is  at  Grand  Tower.  Perhaps 
here  was  the  barrier  which  held  the  waters  back 
at  the  west,  until  the  Mississippi  gradually  sawed  the 
notch  which  drained  the  inland  sea.  At  the  east, 
however,  we  know  no  barrier  adequate  to  hold  the 
lakes  at  the  level  of  the  220  feet  terrace  of  Lake  Erie. 
The  high  flood  of  the  lakes  must  have  been  182 
feet  higher  than  the  escarpment  or  wall  of  rock  back 
.  of  Lewiston,  through  which  the  Niagara  River  has 
cut  its  gorge.  Undoubtedly,  this  escarpment,  which 
runs  east  nearly  parallel  with  the  shore  of  Lake 
Ontario,  was  formerly  much  higher  than  at  pres- 
ent ;  but  we  have  no  evidence  that  it  stood  190  feet 
higher  than  in  our  time. 

The  Lewiston  escarpment  is  at  present  38  feet 
above  Lake  Erie,  and  could  have  dammed  the  lake 
to  that  height,  at  any  time  before  the  Niagara 
gorge  was  begun.  The  water,  setting  back  to  the  site 
of  Chicago,  would  have  buried  it  22  feet  deep.  Even 
this  would  overflow  the  present  southern  barrier 
of  Lake  Michigan,  and  inundate  the  prairie  region  of 
Illinois.  Thus,  the  existence  of  a  terrace,  but  38 


The  Floods  of  the  Great  Lakes.  49 

feet  above  Lake  Erie  would  indicate  that  the  Great 
Lakes  once  flooded  the  greater  part  of  the  state  of 
Illinois.  Now,  if  we  examine  the  nature  of  the 
prairie  deposit,  it  presents  every  indication  of  forma- 
tion in  the  bottom  of  a  lake.  Here  is  the  stratified  ar- 
rangement ;  here  are  the  clay  and  marls,  and  here 
are  even  the  shells  of  the  molluscs  which  dwelt 
in  the  water.  These  facts  must  be  borne  in  mind. 

The  high  water  of  the  Great  Lakes  has  occurred  Date  of 
since  the  Drift  was  deposited— since  the  latest  semi-  blehlevel- 
stratified  Drift  was  laid  down.     The  lake  terraces 
rest  on  the  Drift.    All  the  other  lacustrine  deposits 
attending  the  high  water,  rest  on  the  Drift.    The 
entire  broad  region  covered  by  the  high  water  is  Lake 
overspread  by  a  sheet  of  lacustrine  clays  and  thin  deP°8its- 
seams   of  sand.     These  deposits  exhibit  a    regular 
horizontal   stratification.     Occasionally   we    find    a 
bowlder  imbedded  in  them.    Excellent  material  for 
bricks  and  pottery  is  furnished  by  the  clays;  and 
in  many  situations,  as  at  Milwaukee,  the  absence 
of  iron  prevents  the  production  of  a  red  color  in 
burning.    The  famous  "Milwaukee  bricks"  are  of  a 
pale  lemon  color,  or  even,  in  some  cases,  as  white 
as  chalk.    This  sort  of  clay  occurs  on-  both  sides  of 
Lake  Michigan. 

These  lacustrine  deposits  rise  from  the  shore  with 
the  general  slope  of  the  earth's  surface,  to  the  upper 
level  reached  by  them.  The  lowest  beds  come  to  the 
surface  at  the  highest  elevation.  Often  these  are 
sandy ;  and,  becoming  saturated  with  rain  at  the 
surface,  they  convey  a  sheet  of  fresh  water  under  the 
other  deposits  to  the  lower  levels.  These  water-bear- 
ing sheets  pass  under  the  cities  which  have  been 


60        Walks  and  Talks  in  the  Geological  Meld. 

built  in  modern  times  on  the  lacustrine  border.  In 
some  cases,  as  at  Toledo,  and  many  points  on  the 
north  shore  of  Lake  Erie,  artesian  borings  have  been 
carried  down  to  the  water-bearing  strata,  and  thus 
artesian  wells  have  been  obtained. 

River  We  have  been  considering  lake-terraces  and  high 

terraces.  water  in  the  Great  Lakes.  But  every  observer  has 
noticed  terraces  also  along  the  borders  of  rivers.  On 
the  lower  Ohio  they  occur  up  to  160  feet  above  low 
water ;  at  Louisville,  128  feet  above  low  water  ;  near 
Cincinnati,  120  feet.  On  the  Connecticut,  they  range 
from  150  to  240  feet  above  the  modern  flood  level.  On 
the  Missouri  we  find  them  up  to  335  feet ;  on  the 
Athabasca  and  Saskatchewan,  up  to  370  feet.  There 
is  no  need  of  citing  further  ;  for  these  facts  show  that 
the  rivers  in  all  the  northern  parts  of  the  country 
have  been  enormously  flooded,  as  well  as  the  lakes. 
These  terraces,  also,  rest  on  the  top  of  the  Drift 
deposits.  The  flooded  waters,  therefore,  in  general, 
existed  after  the  events  which  left  the  Drift  over- 
spreading the  northern  states. 

Now  let  us  reason  a  moment  from  the  facts  which 
have  been  brought  to  our  notice.  We  have  been  led 
to  speculate  on  the  possible  agency  which  trans- 
ported the  bowlders  from  their  northern  home.  We 
have  been  thinking  of  glaciers  as  a  satisfactory  expla- 
nation. Now,  suppose  there  really  was  a  vast  glacier 
covering  the  country  as  widely  as  the  Drift  at  present 
covers  it.  The  ice  must  have  melted ;  it  is  not  here 
now.  Suppose  it  melted  rapidly  ;  what  enormous 
floods  must  have  been  occasioned  !  How  they  moved 
and  mixed  and  half  assorted  the  sands  and  pebbles  ! 
May  not  such  a  flood  have  produced  the  results  which 


The  Mud  Flat.  51 


we  see  in  the  semi-stratified  Drift  ?  And  then  may 
not  an  excess  of  water  have  remained  in  all  the 
streams  long  after  the  southern  portion  of  the  glacier 
had  disappeared,  and  the  semi-stratified  Drift  had 
been  put  in  place  ? 


VIII.    THE  MUD  FLAT. 

SEDIMENTATION. 

A  FEW  years  ago,  in  ascending  the  valley  of  the  Transport- 
Aar,  in  Switzerland,  I  enjoyed  an  extraordinary  op-  lns  power 
portunity  to  observe  the  action  of  moving  water, 
The  Aar  is  a  turbulent  stream  issuing  from  the  foot 
of  the  Aar  glacier  of  the  Jura  Mountains.  It  comes 
out  of  its  ice-roofed  cavern  milky-white  with  the 
clay  sediment  which  results  from  the  scouring  of  the 
rocks  by  the  sliding  glacier.  The  sharp  collision  of 
transported  rock-fragments  accompanies  the  loud 
roaring  of  the  impetuous  stream.  On  this  occasion, 
the  white  streamlet,  always  rapid,  had  been  swollen 
to  a  furious  torrent  by  a  recent  cloud-burst.  The  tor- 
rent, in  its  rage,  had  rent  all  barriers,  and  coursed 
over  the  adjacent  lands.  Stones,  up  to  several  tons 
in  weight,  had  been  hurled  right  and  left,  as  the 
autumn  wind  disperses  the  light  leaves  of  the  maples 
along  the  street.  Hundreds  of  acres  lay  buried  be- 
neath sand  and  mud,  cobble-stones  and  massive 
rocks.  The  rough  and  rocky  slope  had  received  its 
deposits  ;  the  late  goat  pasture  lay  concealed  beneath 
a  bed  of  stones,  and  the  grassy  flat  was  hidden  by  a 
blanket  of  gravel  and  slime. 


52       Walks  and  Talks  in  the  Geological  Field. 

The  run-        Observe  the  power  of  assortment  exerted  by  the 
ning  water  moving  water.    The  heavier  rocks  were  left  where 

sorts  the 

material  the  most  precipitous  hillside  graduated  into  the 
it  carries.  Bnarp  siOpe.  Here  was  the  first  abatement  of  the 
force  of  the  stream.  It  dropped  what  could  no 
longer  be  moved  by  the  diminished  power  of  the  tor- 
rent. The  smaller  rocks  lay  next  in  order.  Where 
the  sharp  slope  passed  into  a  gentler  grade,  the  still 
waning  force  of  the  maddened  stream  became  insuffi- 
cient to  bear  them  on.  Still  beyond,  on  the  lower 
levels,  the  flood  was  widened,  its  velocity  slackened, 
and  its  transportative  power  so  abated  that  the  aver- 
age sized  cobble-stones  had  to  be  left.  Still  went  on 
the  gravel,  and  found  pause  only  on  the  pastures 
where  domestic  animals  had  been  grazing.  But  the 
sand  was  borne  to  the  level,  and  spread  itself  out  over 
many  an  arable  field  and  fragrant  meadow;  while  the 
fine  alluvial  mud  had  floated  with  the  tired  waters, 
which  sought  out  sheltered  nooks  and  depressions  in 
which  to  rest.  This  was  yesterday.  This  morning 
the  lesson  lay  before  me.  Here  were  effects  of  a  geo- 
logical cause  on  whose  action  the  startled  peasant  yes- 
terday gazed  despairingly. 

Filling  of      Not  far  from  the  home  of  my  boyhood  was  the 
su-earn^    milHPond)  dear  to  every  school-ward  trudging  urchin 
borne  sed-  who  had  to  pass  it,  and  a  Saturday  resort  for  many 
iments.      others  who  lived  in  the  adjoining  "district."    Here 
we  bathed  ;  here  we  fished  ;  here  we  risked  our  lives 
in  shaky  skiffs,  and  astride  of  unmanageable  logs. 
The  water  was  deep  and  clear.    Last  summer  I  vis- 
ited the  old  pond.    The  deep,  clear  water  was  silted 
up,  and  flags  were  thrusting  their  brown  noses  up, 
in  the  sites  where  I  used  to  swim  in  summer  and 


The  Mud  Flat.  53 


skate  in  winter.  Sedges  fringed  the  borders ;  bul- 
rushes, to  their  knees  in  water,  were  holding  posses- 
sion of  land  that  was  expected  to  be,  and  the  en- 
croaching marsh  threatened  to  corner  the  anxious 
perches  and  sunflshes  in  the  last  lingering  bowl  of 
clear  water  close  by  the  decrepit  old  dam.  How 
long,  I  queried,  before  this  mill-pond  will  be  a 
swamp  ?  Is  this  the  impending  fate  of  all  our  ponds 
and  lakelets? 

The  first  land-surveyors  of  the  territory  of  Mich-  Examples 
igan  laid  down  on  their  plats  an  extraordinary  num-  *n 
ber  of  swamps  and  bogs.  But  the  early  settlers  of 
Michigan  found  many  of  the  swamps  non-existent ; 
some  were  grassy  plains ;  some  were  quaking  bogs, 
and  others  were  part  marsh  and  part  lakelet.  Dur- 
ing sixty  years,  many  of  the  quaking  bogs  have  be- 
come solid  meadows ;  and  many  of  the  marsh-side 
lakelets  have  totally  disappeared  under  the  encroach- 
ments of  the  growing  marsh.  These  are  geological 
changes,  and  the  geologist's  eye  looks  about  for  the 
causes.  It  is  not  a  far-fetched  solution  to  see  iu  the 
hillside  wash  a  source  of  silt,  which  annually  dimin- 
ishes the  depth  of  water  to  a  certain  extent.  And  it 
requires  but  ordinary  sagacity  to  notice  each  decay- 
ing crop  of  grasses,  sedges,  and  rushes  as  the  source 
of  the  dark  peaty  deposit  which  displaces  the  last 
water,  when  other  causes  have  produced  the  requi- 
site shallowness.  We  have  caught  the  marsh-mak- 
ing business  in  the  midst  of  its  accomplishment. 
Short  as  our  lives  are,  each  life  falls  within  the  geo- 
logic age  in  which  vast  results  are  actually  working 
out.  All  these  marshes  have  been  lakes.  If  we  dig 
in  them  we  find  the  bleached  relics  of  the  very  shells 


54       Walks  and  Talks  in  the  Geological  Field. 

which  held  animated  tenants  of  the  vanished  lake- 
let. Thus,  gathering  sediments  add  sheet  after  sheet 
to  the  deposits  which  are  filling  the  larger  as  well  as 
the  smaller  bodies  of  water  which  rest  on  the  earth's 
surface. 

Amount  All  great  rivers  are  enormous  mud-carriers.  The 
sediment  Nile'  tne  Amazons»  tne  Ganges,  the  Hoang  Ho,  the 
Mississippi,  are  great  vehicles  for  the  transport  of 
earthy  substances  from  the  higher  to  the  lower  levels. 
Like  the  Tiber,  their  waters  are  all  "  yellow."  The 
Chinese  have  surpassed  all  other  nations  in  making 
a  proper  name  of  the  generic  description  of  muddy 
rivers.  What  a  potion  is  a  glass  of  Mississippi  water, 
placed  by  the  side  of  one's  plate  in  the  cabin  of  the 
steamer  !  In  thirty  minutes  it  holds  a  deposit  of  im- 
palpable sediment,  which  is  simply  mud.  Think  of 
the  entire  breadth  and  depth  of  this  mighty  stream 
charged  with  earthy  materials  to  such  an  extent. 
What  must  be  the  total  amount  of  matter  car- 
ried down  to  the  Gulf  annually?  The  engineers 
of  the  United  States  have  attempted  to  answer  this 
question.  They  say  that  if  the  annual  discharge  of 
mud  were  brought  together  and  dried,  it  would  form 
a  block  a  mile  square  and  two  hundred  and  seventy- 
eight  feet  high.  Imagine  that  block  lying  on  the 
surface  of  some  level  township.  Then  think  another 
block  on  the  top — the  result  of  another  year's  trans- 
port. Eecall  the  fact  that  the  Mississippi  has  been  at 
this  business  at  least  five  or  six  thousand  years.  Put 
five  or  six  thousand  such  blocks  together ;  the  aggre- 
gate would  be  a  mountain  range. 

There  are  seasons  when  the  proud  river  climbs  over 
its  bounds— climbs  over  the  artificial  restraints  which 


The  Mud  Flat.  55 


have  been  imposed  in  the  form  of  levees.  Water  and 
mud  spread  over  hundreds  of  plantations.  Then,  as 
in  the  overflowing  torrent  of  the  Aar,  the  slackened 
motion  of  the  water  allows  the  fine  sediment  to  sub- 
side. Corn  lands  and  cotton  lands  receive  a  new  con- 
tribution of  fertilizing  material.  Such  service  the 
Nile  performs  for  Egyptian  agriculture — under  the 
rule  of  the  Khedives,  as  during  the  reigns  of  the 
Pharaohs.  Thus  the  deltas  of  the  great  rivers  are  Deltas, 
formed.  Still  the  great  preponderance  of  river  silt 
passes  on  to  the  outlets.  Not  only  the  floating  sedi- 
ment, but  a  large  amount  of  bottom  mud,  too  thick 
to  float  and  too  loose  to  lie  unmoved.  This  the 
stream  pushes  along  into  the  sea — year  by  year  into 
deeper  and  deeper  water,  as  the  shallower  shore  re- 
gion becomes  silted  up.  This  is  the  bar.  By  the 
annual  extension  of  the  bar,  the  delta  gradually  pro- 
trudes a  tongue  of  land  into  the  sea.  Look  at  a  map 
of  the  mouth  of  the  Mississippi,  or  the  Nile,  or  the 
Ganges.  Often  the  piled  up  bar-material  so  obstructs 
the  exit  through  the  main  channel,  that  the  water 
sets  back  up  the  stream  during  some  flood,  overflows 
its  banks,  and  seeks  a  new  route  to  the  sea.  This 
may  be  many  times  repeated.  So  these  great  rivers 
acquire  numerous  outlets.  Look  at  the  map  again. 
The  bar  at  the  mouth  of  the  Mississippi  extends 
three  hundred  and  thirty-eight  feet  into  the  Gulf 
annually. 

Much  of  the  Mississippi  sediment,  therefore,  lies  gedimen- 
somewhat  permanently  on  the  Gulf  bottom,  near  the  tation  in 
shore.  Through  this  Engineer  Eads  has  staked  out  a 
channel,  to  which  the  current  of  the  Mississippi  is 
confined  after  entering  the  Gulf,  until  deep  water  is 


56       Walks  and  Talks  in  the  Geological  Field. 

reached.  Its  velocity  is  thus  preserved,  and  its  mud 
is  carried  beyond  into  the  deeper  basin.  Before  this 
improvement  the  water  spread  out  fan-like,  and 
slackened  its  velocity  to  such  an  extent  that  the  mud 
was  deposited  in  a  region  where  the  water  was  al- 
ready so  shallow  that  navigation  became  seriously 
obstructed. 

Still,  some  of  the  sediment  floats  on  beyond  the 
bar.  There  is  a  current  in  the  Gulf  which  sets  east- 
ward along  the  northern  border,  and  bears  Missis- 
sippi sediment  as  far  as  the  straits  of  Florida.  The 
fine  impalpable  dust  finally  comes  to  rest  on  the 
bottom  of  the  Gulf. 

A  thousand  rivers  thus  are  bringing  their  contribu- 
tions to  the  sea.  Around  ten  thousand  miles  of  coast, 
the  sea  itself  is  battering  down  the  land.  The  coarser 
fragments  are  left  along  the  beach.  The  enfeebled 
action  of  the  retreating  surf  bears  some  distance  sea- 
ward the  smaller  fragments  and  the  pebbles— rolled 
and  rounded  on  the  beach.  The  finest  sediments 
have  no  opportunity  to  subside  till  floated  far  from 
shore.  Thus  the  same  assortment  is  exerted  which 
we  saw  effected  by  the  torrent  of  the  Aar.  The 
ocean's  bottom  lies  covered  to  a  vast  extent  with 
sheets  of  sedimentary  materials  which,  near  the 
shore,  are  coarse,  and  remoter  from  shore  are  progres- 
sively finer,  as  far  as  the  finest  sediments  are  floated. 
This  process  goes  forward  before  our  eyes  ;  it  has  been 
continued  during  all  the  thousands  of  ages  past,  since 
the  ocean  first  came  into  existence.  How  many 
layers  must  there  be  ?  How  many  feet  of  sediments 
have  been  piled  up?  What  conditions  have  they 
assumed  while  the  geologic  seons  have  rolled  by  ? 


The  River  Gorge.  57 


IX.     THE  EIVEE  GORGE. 


WHENCE  come  the  sediments  which  muddy  the  The  source 

of  sedi- 
ments. 


rivers  and  fill  the  lakelets,  and  make  even  the  oceans  of  sedl" 


shallower?  These  sediments  must  all  come  from 
some  source  where  they  existed  as  solid,  massive  con- 
stituents of  our  planet.  They  are  portions  of  the 
planet  transported  from  one  position  to  another. 
Their  transportation  changes  the  figure  of  the  planet. 
Every  film  of  sediment  proclaims  that  the  fashion  of 
the  planet  has  been  worked  over  to  some  extent. 
The  making  of  the  planet  has  been  merely  a  progres- 
sive changing  of  the  fashion  of  the  materials  of 
which  it  is  composed.  If  the  completed  planet  as  we 
see  it  is  the  product  of  geological  forces,  then  the 
work  of  sedimentation  proceeds  by  means  of  forces 
which  are  geological.  The  filling  of  boyhood's  mill- 
pond  was  a  geological  work.  The  slime  settled  by 
the  roadside  is  a  geological  phenomenon.  These  are 
results  accomplished. 

The   sediments    have    been    brought   by   moving  Thesedi- 
waters;  we  must  therefore  trace  the  waters  to  their  ™^gr 
sources  ;  we  must  retrace  their  course  from  the  higher  traced, 
level.    Obviously,  the  roadside  slime  has  descended 
the  rill-ways  from  the  middle  of  the  street ;  from  the 
hill-slope  down  which  a  portion  of  the  water  de- 
scended.   Some  water  flowed  down  the  field-slope, 
moved  under  the  fences,  and  found  its  course  to  the 
roadside  pool,  bringing  as  much  sediment  with  it  as 


THE   WATER  POCKET  CANON,   UTAH. 
Illustrating  the  effects  of  water  erosion. 


The  River  Gorge.  59 


it  had  power  to  bear.  The  corn-fields  have  been 
taxed ;  the  earth  built  into  the  highway  has  been 
stolen ;  the  form,  and  bulk  of  the  hill  have  been 
changed.  So  the  farmer's  fields  contributed  the 
material  which  lies  in  the  bottom  of  the  mill-pond. 
To  some  extent,  the  fields  have  been  scraped  down 
and  impoverished.  There  lies  the  farmer's  property 
spread  over  a  surface  which  forms  the  floor  of  the 
sunfishes'  home. 

Over  every  square  mile  flows  some  stream.  The 
smallest  stream,  as  well  as  the  largest,  occupies  a 
valley ;  and  down  its  slopes  descend  the  sediment- 
laden  drainage  waters  which  seek  the  stream  to  join 
in  its  journey  to  the  lower  levels.  Follow  the  stream- 
let. Along  every  rod  of  its  course  we  find  discharged 
during  a  rain  the  muddy  washings  of  the  land.  The 
streamlet  grows.  Many  a  lateral  rill  brings  in  its 
contribution  from  the  fields  which  stretch  in  another 
direction.  Our  streamlet  flows  on,  and  sooner  or 
later  it  discharges  its  burden  in  some  larger  stream, 
which  has  already  grown  to  its  present  volume  by 
the  contribution  of  a  score  of  streamlets  higher  up 
the  valley.  All  are  merged  together  ;  but  we  are  sure 
the  water  and  the  mud  from  our  own  village— our 
own  farms — are  there  with  the  rest.  The  stream 
moves  on — it  never  rests— and  it  grows  as  it  moves. 
It  courses  across  a  state;  it  marks  a  boundary  be- 
tween states.  Men  have  made  it  a  vehicle  for  float- 
ing logs  ;  a  highway  for  skiffs  and  barges.  Now,  the 
more  pompous  stream  styles  itself  a  river.  It  has- 
tens to  join  the  Ohio  and  share  in  the  dignity  of 
floating  steamboats  and  carrying  on  the  commerce  of 
a  populous  valley.  The  Ohio  has  even  surpassed  the 


60       Walks  and  Talks  in  the  Geological  Field. 

tributary  by  which  we  have  been  led,  in  taking  on  its 
cargo  of  mud.  We  stand  in  the  middle  of  the  sus- 
pension bridge  at  Cincinnati  and  look  down  on  the 
yellow  surface  of  the  great  stream.  There  go  the  con- 
tributions from  half  a  dozen  states.  There  goes  the 
soil  filched  from  our  garden,  or  torn  from  our  new 
made  road,  two  hundred  miles  away.  We  know  it  is 
there. 

Drainage  Look  on  the  map  and  notice  how  many  rivers  are 
areas.  bringing  their  sediments  to  the  Ohio.  Trace  these 
tributaries  to  their  sources.  From  how  wide  a  terri- 
tory is  the  mud  gathered  which  thus  rushes  down 
with  the  main  river  ?  Notice  that  the  Ohio  carries 
its  burden  to  the  Mississippi.  Look  again  upon  the 
map  and  see  how  many  other  great  rivers  bring  the 
mud  from  other  far-off  regions  to  concentrate  it  all  in 
the  mighty  Father  of  Waters.  Here  float  sediments 
from  western  New  York,  from  West  Virginia,  from 
the  Ozark  Mountains,  from  the  Cumberland  Table 
Land,  from  Minnesota,  and  the  Indian  Territory. 
Here  in  this  resistless  tide  floats  the  identical  soil 
which  was  washed  from  Farmer  Jones's  potato  field. 
In  this  view,  consider  the  great  Missouri.  It  pours 
its  yellow  stream  into  the  clearer  tide  of  the  Missis- 
sippi a  few  miles  above  St.  Louis.  I  have  stood  on 
the  deck  of  a  steamer  between  Alton  and  St.  Louis 
and  looked  down  on  the  Missouri's  turbid  volume 
pushing  far  into  the  Mississippi,  and  retaining  for 
miles  a  distinct  boundary  between  the  waters  of  the 
two  rivers.  It  appears  that  the  contributions  from 
the  far  northwest  exceed  all  those  from  the  east. 
Follow  the  whirling  tide  of  the  Missouri  upward 
toward  its  sources.  There  staud  great  cities  on  its 


The  River  Gorge.  61 


alluvial  banks.  The  crumbling  bluffs  by  spells  slide 
into  the  river.  Above  the  limits  of  city  populations 
the  river  is  already  gathering  in  the  mud  destined  to 
journey  to  the  Gulf  of  Mexico  —  mud  which  has 
already  been  floated  from  some  remoter  region  and 
deposited  here  at  times  of  overflow.  Here  comes  the 
Niobrara,  with  slime  from  the  prairies  of  Nebraska ; 
the  Cheyenne,  with  washings  from  the  mining  camps  . 
in  the  Black  Hills  ;  the  Little  Missouri  and  Yellow- 
stone, with  sands  worn  from  the  Big  Horn,  the 
Wind  River,  and  the  Snow  Mountains ;  here,  on  a 
grassy  plain,  unite  the  Jefferson,  Madison,  and  Gal- 
latin  tributaries,  which  bring  the  dust  of  the  conti- 
nent from  the  high  water-shed  of  the  Red  Rock 
Mountains,  which  parts  the  continental  drainage  to 
opposite  points  of  the  compass.  It  is  a  bewildering 
breadth  and  complexity  of  operations.  Over  every 
foot  of  this  wasting  expanse  the  land  is  yielding  to  the 
corrosive  action  of  rivers  and  rains  and  frosts.  The 
proud  mountain  domes  and  pinnacles  are  coming 
down  to  acknowledge  the  supremacy  of  the  powers 
of  denudation.  The  Rocky  Mountains  have  begun 
their  journey  to  the  Gulf  of  Mexico.  Cubic  miles  of 
their  granitic  substances  are  buried  in  the  delta  of 
Louisiana  and  the  bar  of  the  Mississippi. 

Every  river,  in  its  search  for  a  resting-place,  has  Examples 
cut  a  way  of  even  grade  across  the  inequalities  of  the  of  river 
land,  and  the  rubbish  has  been  dumped  somewhere —  gorges- 
in  alluvial  border  or  broad  delta,  or  seaward  rolling 
bar.    The  Yampa  has  sawed  a  broad  gash  through 
the  Uinta  range  on  its  way  to  the  Green  River.    The 
Green  has  cut   a  dark   chasm   down   through   the 
plateaus    of  Colorado   to   the   river   whose   colored 


62       Walks  and  Talks  in  the  Geological  Field,. 

waters,  poured  in  from  the  snow-born  floods  of  the 
Rocky  Mountains,  gave  name  to  the  river  and  the 
state.  The  Colorado,  with  augmented  force,  has  dug 
a  deeper  and  a  wider  caflon  through  the  shattered 
terraces  of  the  southern  half  of  the  state.  The 
"  Grand  Canon  "  sinks  vertically  six  thousand  feet 
through  the  rocks— a  terrific  gash,  like  a  sabre-cut 
from  some  of  the  powers  of  Nature. 

"  It  looks  as  if  broken  by  bolts  of  thunder, 
Riven  and  driven  by  turbulent  time." 

So  a  hundred  rivers  of  the  far  west  have  scored  the 
land.  So  the  Cumberland,  the  Kentucky,  the  Hud- 
son, the  James,  the  Mississippi,  by  gentle  worrying 
of  the  underlying  rocks,  have  plowed  out  channels 
whose  steep  walls  rise  as  high  as  the  smoke  from  the 
steamer  which  utilizes  the  water-way.  We  have  not 
seen  these  works  begun  ;  but  we  see  them  in  progress; 
and  we  feel  bound  in  reason  to  infer  that  the  rivers 
have  worked  in  the  distant  past  as  they  are  working 
before  our  eyes. 

Mountains  There  are  other  erosions,  however,  which  were 
denuCUm~ effected  not  onlv  before  human  times,  but  by 
dation.  agencies  which  have  disappeared  from  existence. 
There  are  the  Catskill  Mountains — essentially  a  mere 
wall  of  horizontally  laid  slabs  of  red  sandstone. 
These  mountains  must  be  a  remnant  of  a  broad  for- 
mation once  stretching  far  east  and  west.  The  forces 
of  erosion  have  worn  away  the  formation  on  both 
sides,  and  the  Catskills  stand  forth  a  feature  of  relief 
as  the  statue  emerges  from  the  block  of  stone  under 
the  chisel  of  the  sculptor.  Such,  too,  is  the  Cumber- 
land Table  Land,  high  upraised  like  a  mountain, 
but  yet  not  uplifted.  It  is  a  mere  salience  resulting 


The  River  Gorge.  63 

from  the  vast  erosions  that  have  taken  place  along  its 
western  border.  In  central  Tennessee,  indeed,  this 
erosive  process  has  excavated  a  basin  a  hundred  miles 
in  diameter,  bounded  on  all  sides  by  the  ragged 
edges  of  the  formations  which  were  left. 

So  this  completed  work  of  erosive  powers  which  Outliers, 
have  retired  from  action  is  commemorated  in  many  a 
monument-like  outlier  in  Wisconsin  and  Minnesota. 
A  great  formation  which  once  overspread  many  a 
township  has  all  been  carried  away,  save  here  and 
there  an  isolated  remnant  which  lies  like  an  island  in 
the  midst  of  geology  of  a  different  character.  It  is 
the  Potsdam  Sandstone  which  has  been  thus  eroded  ; 
but  wide  areas  still  remain,  and  underlie  portions 
of  those  states.  Similar  are  the  columns  in  Monu- 
ment Park,  and  the  ruins  in  the  "  Garden  of  the 
gods."  Like  the  great  basin  of  central  Tennessee 
are  many  of  the  excavations  in  the  Bad  Lands  of  the 
Upper  Missouri  and  in  New  Mexico. 

These  two  great  processes,  erosion  and  sedimenta- 
tion, must  be  vividly  appreciated.  The  whole  history 
of  the  visible  land  has  consisted  chiefly  of  upbuild- 
ing and  destruction,  rebuilding  and  disintegration, 
by  the  action  of  forces  which  have  left  gigantic 
monuments  of  their  former  power,  and  are  even  in 
our  times,  working  on  a  scale  large  enough  to  illus- 
trate to  us  how  the  foundations  of  the  land  were  laid, 
and  how  the  face  of  the  earth  has  been  carved  into 
the  fashion  it  presents  to  our  interested  eyes. 


64        Walks  and  Talks  in  the  Geological  Field. 


X.    A  WALK  UNDEE  THE   SEA. 

WHAT  GOES  ON  IN  THE  OCEAN  DEPTHS. 

The  sea.  THE  sea  has  always  inspired  the  wonder — often  the 
veneration  —  of  mankind.  Its  vastness  and  power 
overwhelm  the  imagination.  Its  permanence,  its  an- 
tiquity, form  a  bewildering  conception.  The  same 
"  far-sounding  sea  r  roared  in  the  hearing  of  the  mar- 
iners of  the  remotest  past.  The  same  ocean  floated 
the  ships  of  the  Tyrians  and  Carthaginians.  A 
"  glorious  mirror,"  as  Byron  conceived  it, 

"  Where  the  Almighty's  form 

Glasses  itself  in  tempests 

Boundless,  endless,  and  sublime, 
The  image  of  eternity— the  throne 
Of  the  invisible." 

Let  us  stand  on  some  bold  headland  and  look  out 
over  the  Atlantic.  Let  us  plant  ourselves  on  Sankaty 
Head,  the  eastern  promontory  of  Nantucket,  itself 
the  "ultima  Thule"  of  New  England.  The  break- 
ers roar  along  the  beach.  Across  the  billowy  blue 
thought  wanders  to  the  European  shore.  Under- 
neath the  ruffled  surface  imagination  pictures  a  world 
Down  of  curious  and  wonderful  existences.  We  go  down 

through     like  tbe  bathers  in  the  sea.    We  pass  the  margin 
the  depths. 

where 

"  The  dreary  back  seaweed  lolls  and  wags." 
We  traverse  the  borders  where  the  brown,  belted 
kelp  sways  to  and  fro  in  graceful  curves.    We  get 


A   Walk  under  the  Sea.  65 

beyond  the  slope  of  stony  bottom  to  the  smooth 
sand.  We  come  to  the  gardens  of  the  rosy-tinted 
sea-mosses— the  Dasya,  the  Grinnellia,  the  Callith- 
amnion;  and  startle  the  blue-fish  and  halibut  in 
their  safe  seclusion.  A  moonlight  gleam  is  here,  and 
the  water  also  takes  on  the  chill  of  evening.  We 
pass  on,  and  attain  a  depth  of  half  a  mile.  Our  feet 
press  into  the  finer  sediments  derived  from  the  land 
— the  dust  of  other  "  continents  to  be."  The  twi- 
light has  faded  into  a  deep  shade.  The  creatures  of 
the  sea  swarm  curiously  about  us,  then  flee  in  terror 
from  our  presence.  We  feel  the  gentle  movement  of 
"a  river  in  the  ocean,"  but  the  surface  disturbances 
do  not  reach  even  to  this  depth.  A  change  of  cli- 
mate impresses  itself  on  our  sensations.  The  water 
where  we  started  in  had  a  temperature  of  sixty  de- 
grees—here it  is  forty.  We  descend  to  the  depth  of 
a  mile  under  the  sea.  The  curiously  gazing  species 
of  the  shallower  water  appear  no  more.  Their  home 
is  the  zone  which  now  stretches  above  our  heads. 
The  green  and  rosy  sea-mosses  never  venture  here. 
We  are  in  total  darkness ;  no  chlorophyll  tints  the 
growths  of  the  vegetable  kingdom.  Here  are  only 
stony,  white  calcareous  algse  and  silicious  diatoms  of 
microscopic  minuteness.  We  feel  our  slimy  path 
down  to  the  deeper  profound.  Above  us  now  float 
two  miles  of  black  sea.  Any  surface  fish  brought 
down  here  perishes  from  the  effect  of  enormous  pres- 
sure, if  possessing  an  air-bladder.  If  it  have  none,  the 
fish  becomes  torpid,  and  finally  dies.  We  are  here, 
probably  miles  from  the  shore — that  varies  with  the 
steepness  of  the  slope.  The  sediments  which  the 
rivers  have  brought  to  the  ocean  have  mostly  been 


66       Walks  and  Talks  in  the  Geological  Field. 

deposited  between  our  starting  point  and  this.  But 
here  still  are  some  of  the  finest  particles  contributed 
by  the~land — slime  from  Louisiana,  from  Chautau- 
qua,  from  the  Rocky  Mountains,  from  our  native 
town.  Will  these  far-brought  and  commingled 
atoms  ever  see  daylight  again  ?  We  are  standing  on 
the  border  of  the  vast  abyss  which  extends  over  half 
the  area  of  the  earth.  It  is  an  undulating,  silent 
desert. 
Physical  The  pressure  on  us  in  this  abysmal  region  is  four  or 

of  the"011  five  tons  to  everv  S(luare  inch-  The  water  is  ice-cold 
deep  sea.  everywhere.  The  darkness  absolute  and  palpable. 
A  curdling  revulsion  of  feeling  and  purpose  seizes 
us.  We  halt  and  reflect.  We  turn  our  eyes  upward 
with  a  painful  longing  for  the  ' '  holy  light,  offspring 
of  heaven  first-born."  Only  the  black  ceiling  ap- 
pears. Two  miles  above  us  is  the  sunny  sea,  where 
all  the  blue  of  a  genial  sky  beams  down.  There  float 
the  ships  in  summer  calm  upon  a  "painted  ocean," 
or  tossed  and  rent  by  the  winter  tempest  which  in- 
spires the  waves  with  madness.  But  no  summer  and 
winter  vicissitudes  are  here.  No  sunlight  ever  pen- 
etrates this  Cimmerian  gloom.  No  sunrise,  or  noon- 
day, or  sunset  is  ever  known.  As  it  was  when  the 
Garden  of  Eden  was  first  consecrated  to  man,  so  it 
has  remained  and  must  remain.  Not  even  the  crash 
of  thunders  or  the  roar  of  tempests  can  be  heard. 
The  huge  wave,  crested  with  elemental  fury,  rolls 
on,  but  makes  no  stir  in  the  stillness  and  stagnation 
of  the  abysmal  realm. 

Giobiger-       When  we  crossed  the  borders  of  this  dark  and  silent 

ina  ooze.     abySS)  our  feet  sank  jn  a  wnite  pasty  slime  which  has 

been  designated  "  Globigerina  ooze."    The  dredges  of 


A  Walk  under  the  Sea.  67 

the  Challenger  and  the  Albatross  have  been  down 
here,  hung  by  a  piano  wire  over  the  stern  of  the 
vessel,  and  samples  of  this  ooze  have  been  studied. 
We  find  it  composed  chiefly  of  microscopic  dead 
shells  called  Fo-rawA-niff-e-ra^  together  with  others 
called  Pter'-o-pods.  The  little  creatures  which 
formed  the  shells  do  not  live  here ;  they  dwell  in 
calm  zones  of  water  far  above.  When  the  conscious 
animal  ceases  to  live,  its  tiny  house  sinks  down  into 
this  dark  world.  And  thus,  as  the  ages  roll  by,  the 
fine  chalky  rain  slowly  accumulates  upon  the  bottom. 
When  this  ooze  is  dried  and  hardened,  it  resembles 
the  chalk  of  Europe  ;  and  when  that  is  microscopic- 
ally examined,  we  find  in  it  the  same  little  Forami- 
nifera. 

We  have  groped  our  way  down  three  and  four  ciayooze 
miles  beneath  daylight.    A  sort  of  ooze  still  over-  and  v°l- 

canic 

spreads  the  bottom  ;  but  it  is  not  the  Qlobigerina  and  dust. 
Pteropod  ooze.  It  is  a  fine  rusty  clay.  But  the 
white  shells  are  not  wanting  because  the  tiny  crea- 
tures which  secrete  them  are  not  overhead.  They 
swarm  there  as  elsewhere,  far  from  land  with  other 
pelagic  forms.  But  the  fragile  matter  of  the  shell  is 
dissolved  before  it  reaches  this  great  depth.  Only 
the  aluminous  and  insoluble  constituent  reaches  the 
bottom.  This  clay  ooze  possesses  other  interest. 
Disseminated  through  it  are  minute  crystals  of  such 
minerals  as  escape  through  the  throats  of  volcanoes 
into  the  upper  air.  Here  are  the  dust  particles  which 
have  imparted  a  ruddy  glow  to  many  a  past  sunset. 
Once  the  source  of  the  roseate  glory  of  the  twilight 
hour,  they  lie  now,  in  impenetrable  darkness  and  the 
repose  of  death.  How  changed  the  fortune  of  the 


68        Walks  and  Talks  in  the  Geological  Field. 

little  particle.  It  floated  for  months  in  the  upper 
thin  air — in  the  film  of  space  which  separates  earth 
from  heaven— borne  hither  by  the  simoon,  thither  by 
the  anti-trades,  hurled  in  the  vortex  of  a  cyclone  and 
precipitated  in  mid-ocean  by  a  down-falling  mass  of 
vapor.  Then,  perhaps,  seized  by  the  waves,  and 
rocked  and  beaten  at  the  surface  till  it  reached  a  zone 
of  calm,  it  began  its  silent  descent  into  the  dark 
world  where  it  is  destined  to  rest  undisturbed  for  cen- 
turies. 

Cosmic  Here  too  is  cosmic  dust.  The  seeds  of  worlds  have 
dust.  been,  sprinkled  through  space,  and  some  of  them  have 
been  planted  in  the  soil  of  this  abyss.  These  minute 
globules  of  magnetic  iron  were  sparks  emitted  from  a 
burning  meteor.  The  meteor  was  a  small  mass  or 
particle  of  material  stuff  coursing  swiftly  through 
the  cold  interplanetary  spaces.  It  pierced  the  atmos- 
phere of  the  earth  ;  the  friction  resulting  ignited  the 
meteor,  and  for  a  brief  moment  it  painted  a  fiery 
streak  in  its  flight,  when  all  had  been  transformed  to 
ashy  particles  which  floated  in  the  air  like  volcanic 
dust,  until  it  found,  at  last,  a  resting  place  in  the  cold 
bed  of  the  Atlantic.  What  a  reversal  of  fortune  was 
here !  The  particle  might  have  swept  on  through 
space,  as  many  of  its  companions  did,  until  it  became 
part  of  a  glowing  comet.  Perhaps  it  once  shone  in  a 
star — now  it  is  dead  for  a  cycle  of  ages.  It  is  an  im- 
pressive thought  that  here,  in  this  rayless  night,  we 
find  the  black  ruins  of  a  star. 

We  still  stand  wondering  over  the  scene  which  sur- 
rounds us.  How  oppressive  is  this  silence.  From 
age  to  age  this  reign  of  death  persists.  A  chill  which 
is  more  than  icy,  pierces  us  to  the  marrow.  Some- 


A  Walk  under  the  Sea. 


times,  as  we  grope  through  the  Egyptian  gloom,  we 
kick  the  bones  of  aquatic  creatures  which  have 
perished  in  the  water  above  us.  Often  their  kind  is 
still  in  existence  ;  but  sometimes  their  species  are 
long  extinct.  Here  are  teeth  of  sharks  and  ear-bones 
of  whales  which  have  lain  during  geologic  ages. 
Grand  vicissitudes  have  passed  by,  which  trans- 
formed the  aspect  of  continents,  but  these  relics  lay 
here  undisturbed — unburied— so  slowly  do  the  sedi- 
ments accumulate. 

But  there  is  indeed  life  here.  Sparse,  quaint  life ;  Life, 
and  the  species  are  of  archaic  and  embryonic  forms  ; 
that  is,  they  resemble  creatures  which  lived  in  the 
earlier  ages  of  the  world,  or  creatures  which  have 
undergone  but  a  part  of  their  development — crude, 
uncouth,  and  alien  to  the  modern  world.  Here  are 
Crinoids,  or  Stone  Lilies,  which,  in  most  other  Crinoids. 
waters,  have  perished  from  the  earth.  They  are  an 
antique  type.  But  from  deep  waters  off  the  coasts  of 
Florida  and  Norway,  comes  up,  with  other  forms, 
Rhiz-oc'-ri-nus,  a  genus  which  disappeared  from  shal- 
low seas  unknown  millions  of  years  ago ;  but  here, 
where  nothing  changes,  it  has  perpetuated  its  ex- 
istence through  half  the  history  of  the  world.  Be- 
tween death  and  the  changeless  life  which  here 
reigns,  the  difference  is  slight. 

Still  more  startling  in  their  grotesqueness,  are  some  Fishes. 
of  the  fishes  which  lie  here  more  than  half  buried  in 
the  mud.  Here  is  one  fashioned  like  a  scoop-net. 
The  long,  slender  body  is  the  handle,  and  the  net  is 
an  enormous  pouch  under  the  chin,  which  would 
take  in  the  whole  of  the  body  three  times  over. 
Another  hangs  like  an  open  wide-mouthed  meal-bag. 


70       Walks  and  Talks  in  the  Geological  Field. 

In  this  case,  also,  the  bag  hangs  suspended  from  the 
part  where  the  throat  should  be.  The  diminutive 
body  is  noticed  as  an  appendage  attached  to  the  back 
side  of  the  bag.  It  is  known  by  the  fins.  Four  of 
these  bodies  might  be  contained  in  one  pouch.  A 
different,  but  equally  erratic  form  brandishes  an  at- 
tenuated body  like  a  whip-lash  appended  to  an  enor- 
mous head,  exposing  an  eye  which  is  nearly  half  its 
own  diameter.  Still  again,  we  note  a  shark-like  form, 
with  enormous  gape  and  horrid  teeth,  having  a  range 
of  spines  along  each  side  of  the  slender  body,  above 
and  below,  and,  most  curious  of  all,  a  long,  thread- 
like organ  depending  from  beneath  the  chin,  with  a 
tassel-like  tentacle  bearing  structures  for  feeling,  at 
the  end. 

But  see  !  somebody  is  here  with  a  lantern.  How 
sleepily  the  light  gleams  in  the  darkness.  There  is 
no  fire  in  it.  Something  it  is.  An  animated  lantern. 
A  lantern  without  a  flame.  It  is  another  strange  fish. 
It  is  phosphorescence  which  gleams  mildly  from  his 
shiny  sides.  Still  another  lantern-bearing  fish.  Here 
are  luminous  plates  beneath  the  eyes  ;  behind  them, 
in  a  cavity,  retinal  tissue,  as  if  these  structures  were 
planned  for  eyes  ;  but  they  are  not  eyes.  Real  eyes 
are  present.  We  discover,  then,  faint  relief  from  the 
palpable  darkness  in  which  we  have  groped. 

But  our  task  is  done ;  our  curiosity  is  gratified ; 
we  have  glimpsed  the  underworld,  and  have  gathered 
observations  on  which  we  shall  ponder  many  a  day. 
Let  us  now,  like  the  heroes  of  epic  song,  ascend  to 
the  light  of  the  upper  world. 


By  the  Rocky   Watt.  71 


XI.    BY  THE  EOCKY  WALL. 

STRATA  AND  THEIR  CLASSIFICATION. 

LET  us  walk  in  front  of  the  precipice  which  frowns  Examples 
along  the  hillside  near  the  village  of  Panama,1  on  of  strata, 
the  west.    It  is  no  more  instructive  than  a  thousand 
other  cliffs,  but  it  may  be  more  convenient  to  reach. 
The  cliff  rises  fifty  or  sixty  feet  and  presents  a  broken 
and  rugged  front.    The  brown  and  yellowish  rock  is 
composed   of  fine  silicious  grains,   with  small   im- 
bedded pebbles,  and  thus  answers  the  description  of  a 
conglomeritic  sandstone.    The  face  of  the  cliff  shows  congiom- 
several  yawning  fissures  extending  from  bottom  to  erates- 
top.      The    winter  snow  drifts  into  these  in    such 
abundance  as  to  remain,  sometimes,  till  midsummer. 
One  of  these  chasms  is  known,  therefore  as  the  "  Ice 
House."      You  observe  that  this  precipice  is  com- 
posed of  layers  of  sandstone  piled  one    above    the 
other.    These  are  strata,  and  the  whole  formation  is 
stratified.     [Notice    that    one  of    these    layers    is  a 
stratum— not  "a  strata";  and  we  must  never  say 
"stratas."]     You   observe,  also,   that  some  of  the 
strata  are  composed  of  lamince  which  run  obliquely 
across  the  stratum.     This  is  oblique  lamination.     It  oblique 
is  of  the  same  nature  as  we  saw  in  the  semi-stratified  lam.1- 
Drift.    We  concluded  that  such  mode  of  arrange- 
ment was  caused  by  torrential  action.     A  similar  ex- 
planation is  allowable  here,  but  the  water  was  less 
turbulent ;  it  was,  perhaps,  wave  action  along  a  beach. 

i  Panama,  N.  Y.,  nine  miles  south  of  Chautauqua.   P.  S. 


THE  MU-KU'N-TU-WEAP  ON  THE  VIRGIN  RIVER,  COLORADO. 
Showing  architectural  forms  resulting  from  erosion. 


By  the  Rocky   Wall.  73 

Watkins'  Glen,  at  the  south  end  of  Seneca  Lake,  is  g^aie 
a  wild,  deep  gorge  cut  by  a  stream  which   rushes 
down  from  the  highland  on  its  way  to  the  lake.    It 
is  a  striking  example  of  erosion,  and  the  materials 
carried  away  are  deposited  in  Seneca  Lake.     The 
rocks  here  are  shales.    They  are  thin-bedded,  and  soft 
enough  to  be  cut"  with  a  knife.    We  see  no  oblique 
lamination.    This  is  a  fine  example  of  another  sort 
of  strata.    At  Rochester,  where  the  Central  Railroad  Lime- 
crosses  the  Genesee  River,  a  few  rods  above  the  Falls,  stone> 
we  look  down  into  a  gorge  eroded  by  the  river.     The 
high  walls  of  the  gorge  are  distinctly  stratified  ;  and 
here  many  of  the  strata  are  composed  of  limestone. 
No  traces  of  oblique  lamination  can  be  found  in  lime- 
stones.   If  we  go  to  Portland,  in  Connecticut,  we 
may  look  down  into  wide  and  deep  excavations  in  a 
sandstone  rock  of  a  brownish  color,  and  very  evenly  sand- 
bedded.    Near  Cleveland,  and  at  Berea,  Ohio,  are  ex-  stone' 
tensive  quarries  in  a  grayish  and  bluish  gray  sort  of 
sandstone.    At  Cincinnati,  back  of  the  city,  we  find 
a  steep  slope  formed  of  beds  of  limestone,  shale,  and 
clay.     Descending  the  Mississippi  from  St.  Paul  to 
St.  Louis,  we  see  high  cliffs  of  buffish  strata  over-  etc. 
looking  the  river  at  frequent  intervals — now  on  the 
west,  now  on  the  east.    At  St.  Paul  the  rocks  are  dis- 
tinctly stratified  limestone.     At  Davenport  and  St. 
Louis  we  find  other  kinds  of  limestones. 

Now,  I  have  directed  your  attention  to  these  few 
examples  out  of  hundreds  for  the  purpose  of  en- 
abling you  to  understand  that  everywhere  solid 
rocks  underlie  the  Drift ;  and  that  they  are,  at  least 
very  generally,  stratified  rocks,  and  are  composed 
chiefly  of  sandstones,  limestones,  and  shales.  Let 


74        Walks  and  Talks  in  the  Geological  field. 

Strata  are  us  consider  how  these  solid  strata  have  been  pro- 
sediments,  duced.  None  of  these  have  we  ever  seen  making, 
but  I  think  we  have  seen  a  process  similar  to  rock- 
making  in  the  beds  of  alluvial  matter  deposited  by 
an  overflowing  stream.  In  traveling  down  the  lower 
Mississippi,  we  can  see  from  the  deck  of  the  steamer 
that  the  material  of  the  alluvial  banks  is  horizon- 
tally stratified.  More  strictly  we  should  say  that  it 
is  laminated ;  but  the  nature  of  the  geological  work 
is  the  same  in  either  case.  Now,  if  those  alluvial 
banks  should  become  firmly  consolidated,  they 
would  present  the  appearance  of  some  of  the  rocky 
cliffs— those  in  Watkins'  Glen,  for  instance.  You 
have  also  learned  how  large  quantities  of  sediments 
borne  down  by  rivers  are  carried  out  to  sea  many 
miles,  and  slowly  deposited  on  the  ocean's  bottom. 
These  deposits  must  necessarily  be  in  layers,  each  of 
which  is  spread  evenly  over  the  bottom.  You  re- 
member that  the  distance  to  which  materials  of  a 
certain  degree  of  coarseness  may  be  carried  before 
sinking  to  the  bottom,  depends  on  the  velocity  of  the 
motion  of  the  water.  At  a  certain  place  in  the  sea  the 
velocity  is  undoubtedly  more  rapid  at  one  time  than 
another.  The  motion  is  caused  by  winds,  by  tides, 
and  by  currents.  Therefore,  a  coarser  sheet  of  ma- 
terials will  be  laid  down  at  one  time,  and  a  finer  sheet 
at  another.  The  alternations  of  coarser  and  finer 
render  the  bedded  arrangement  conspicuous.  Very 
likely  the  colors  of  the  sediments  will  vary  also; 
since,  from  one  direction,  they  may  be  supplied  by 
pulverized  limestone,  from  another  by  pulverized 
sandstone,  and  from  another  by  pulverized  shale, 
which  may  be  blue,  red,  or  black.  We  noticed,  too, 


By  the  Rocky  Wall,  75 

in  our  walk  under  the  sea,  that  sedimentary  mate- 
rials are  spread  over  all  the  slope  of  the  ocean's  floor, 
within  fifty  or  a  hundred  miles  of  the  land — often 
much  farther,  if  the  shore  is  "  shelving  "  or  the  cur- 
rents are  favorable. 

These  various  indications  compel  us  to  adopt  the  sordid  by 
conclusion  that  water  has  been  the  agent  by  which  water, 
the  materials  of  the  stratified  rocks  have  been  spread 
out  in  broad  beds  or  strata.  But,  though  river  over- 
flows must  leave  the  sediments  in  a  bedded  condi- 
tion, these  beds  are  not  exactly  like  those  seen  in 
great  formations  of  limestone  and  sandstone.  River 
sediments  never  have  so  wide  an  extent  as  the  strata 
which  underlie  a  continent ;  nor  are  they  generally 
so  evenly  bedded  as  our  ordinary  rock-strata.  We 
must  conclude,  therefore,  that  the  watery  action 
which  arranged  the  sediments  from  which  our  rock- 
strata  have  been  formed,  was  a  very  widely  operating 
action.  There  is  no  watery  action  known  sufficiently 
widespread  except  the  action  of  the  ocean.  In  the  Mainly  in 
ocean,  sediments  are  now  settling  down  in  sheets  a  theocean> 
thousand  miles  broad.  This  conclusion  is  a  some- 
what startling  one.  It  implies  that,  wherever  rocky 
strata  exist,  there  the  ocean's  waters  have  stood. 
Rocky  strata  are  found  hundreds  of  feet  above  the 
level  of  the  ocean,  and  the  fact  seems  incompatible 
with  our  conclusion.  The  average  level  of  all  the 
northern  and  northwestern  states  is  from  six  hun- 
dred to  a  thousand  feet  above  the  sea.  If  the  under- 
lying strata  were  deposited  by  the  ocean,  then  either 
the  ocean  has  greatly  subsided  in  later  times,  or  re- 
gions which  were  once  sea-bottom  have  been  exten- 
sively uplifted. 


76       Walks  and  Talks  in  the  Geological  Field. 

Slowly,  Now,  if  all  the  strata  which  underlie  the  land  are 
formed  from  marine  sediments,  the  time  required  for 
their  accumulation  must  have  been  enormous.  We 
have  made  observations  along  the  sea-shore,  and 
have  formed  some  conception  of  the  rate  of  sedimen- 
tation over  a  belt  near  the  land.  There  are  times 
when  violent  winds  cause  the  waves  to  wear  down 
the  shore  at  such  a  rate  that  the  sea,  for  a  mile  from 
shore,  becomes  turbid  with  sediments.  This  has 
Near  been  seen  often  at  Long  Branch  and  Coney  Island, 
shore.  gu^  these  periods  are  of  short  duration,  and  the 
deposits  at  the  distance  of  ten  miles  from  land  are 
no  longer  conspicuous.  In  the  vicinity  of  coral  reefs 
and  islands  the  attrition  of  the  waves  imparts  a 
milky  complexion  to  the  sea,  especially  during  the 
prevalence  of  a  storm,  and  the  calcareous  particles 
are  floated  sometimes  a  hundred  miles  and  more. 
But  it  is  apparent  that,  as  a  rule,  the  sea  floats  too 
little  sediment  to  build  up  a  formation  in  any  other 
than  a  very  gradual  manner.  We  noticed,  also,  in 
our  walk  under  the  sea,  that  the  bottom  sediments 
grew  thin  with  distance  from  the  shore,  and  that 
those  of  continental  origin  ceased  entirely  at  about 
two  miles  in  depth.  When  now  we  remember  that 
the  stratified  rocks  are  over  a  hundred  thousand  feet 
in  thickness,  we  perceive  immediately  that  the  pro- 
cess of  sedimentation  has  been  an  extremely  long 
one. 

Geological  We  have  then  to  consider  what  changes  may  have 
history  taken  place  in  the  conditions  of  the  world  during  so 
subdi-  e  *ong  a  period.  Probably  the  nature  of  the  sediments 
vided.  has  been  changed  from  time  to  time  by  these  changes 
in  the  physical  conditions  of  the  planet.  We  do  not 


By  the  Rocky   Wall.  77 

wish  to  anticipate  conclusions  to  be  rested  on  facts 
which  have  not  yet  fallen  under  our  observation  ; 
but  everybody  has  noticed  that  the  surface  of  the 
earth  is  undergoing  changes  ;  and  these,  in  thou- 
sands of  years,  must  aggregate  amounts  which  trans- 
form the  aspects  of  the  planet.  We  have  lived  to 
see  lakelets  filled ;  new  channels  formed  for  great 
rivers  ;  ocean  beaches  consumed  by  the  waves  ;  hun- 
dreds of  miles  of  continental  coasts  upraised  or 
sunken— as  in  Chili,  Scandinavia,  and  Greenland  ; 
new  islands  bursting  into  view ;  whole  provinces 
shattered  by  earthquakes.  Suppose  our  observation 
extended  back  a  million  years,  and  the  tenor  of 
events  had  been  the  same  as  in  modern  times  ;  is  it 
not  certain  that  changes  must  have  aggregated  to 
such  an  extent  that,  waking  at  times  to  distinct 
consciousness  of  the  greatly  changed  conditions,  we 
should  from  seon  to  aeon  have  felt  ready  to  declare  a 
new  chapter  of  the  world's  history  had  begun  ?  Ge- 
ologists have  considered  these  facts,  and  have  set- 
tled on  the  principle  that  the  long  history  of  sedi- 
mentation has  been  divided  into  seons  corresponding 
to  successive  conditions  of  the  world.  Names  have 
been  assigned  to  these  seons.  Thus,  the  first  series  of 
sediments  formed  the  strata  which  lie  deepest  of  all. 
They  are  called  Eozoic,  and  the  seon  during  which 
they  were  accumulating  is  the  JEozoic  ^Eon.  We  will 
not  pause  here  to  inquire  what  these  sediments  rested 
on — in  other  words,  what  kind  of  rocks  formed  the 
bed  of  the  sea,  at  the  beginning  of  that  ^Eon. 

The  Eozoic  GREAT  SYSTEM  of  strata  is  at  least  The  great 
fifty  thousand  feet  thick.     In  the    next   aeon   the  rock 
changed  conditions  gave  origin  to  changed  strata.  SyS 


78       Walks  and  Talks  in  the  Geological  Field. 

They  constitute  a  Great  System  known  as  the  PALAE- 
OZOIC ;  and  the  time  during  which  this  system  of 
strata  was  accumulated,  is  the  PALAEOZOIC  JEox. 
Next  after  this  came  the  MESOZOIC  ^EoN,  during 
which  the  MESOZOIC  GREAT  SYSTEM  of  strata  was 
accumulated.  Lastly,  followed  the  C^EN'-O-ZO-IC 
-<EoN,  which  continues  to  the  present.  The  strata 
formed  constitute  the  C^NOZOIC  GREAT  SYSTEM. 


XII.     MYSTERIOUS  FORMS  OF  LIFE. 


EVERYONE  has  noticed  the  curious  forms  found  in 
the  Drift,  which  so  much  resemble  shells  and  corals, 
and  buttons  or  beads.  Often  they  lie  loose  in  the 
soil ;  and  often  we  see  them  imbedded  in  fragments 
of  limestones  and  sandstones  which  are  sometimes 
bowlders  transported  from  a  distance,  and  sometimes 
fragments  derived  from  a  neighboring  ledge  or  out- 
crop of  stratified  rocks.  In  the  cliffs  at  Panama  are 
occasional  traces  of  shells,  both  bivalve  and  univalve. 
The  latter  is  a  little  shell  three  quarters  of  an  inch 
in  diameter,  and  closely  coiled  almost  in  a  plane,  like 
a  watch  spring.  I  have  been  amused  to  hear  some 
of  these  forms  like  bivalve  shells  called  "petrified 
butterflies."  Through  western  New  York,  Ontario, 
Michigan,  Ohio,  and  Indiana  we  find  in  the  Drift 
innumerable  masses  popularly  known  as  "petrified 
honeycomb,"  and  "petrified  wasp-nest."  There  are 
also  quantities  of  little  flat  discs  like  "  buttons,"  each 
with  radiating  strise  or  other  decorations,  and  having 


Mysterious  Forms  of  Life.  79 

a  hole  in  the  middle,  as  if  intended  to  be  strung  like 
beads.  These  have  sometimes  been  styled  "  St.  Cuth- 
bert's  beads." 

These  curious  forms,  so  much  like  animal  struc-  oidtheo- 
tures,  were  wondered  over,  hundreds  of  years  ago.  ries  of 
Very  few  persons  would  then  entertain  the  suggestion 
that  they  are  real  relics  of  living  things.  They  in- 
deed bear  the  similitudes  of  marine  creatures ;  but 
such  they  cannot  be,  it  was  argued,  because  they  lie 
hundreds  of  feet  above  the  sea.  Some  of  the  early 
Italian  writers  attributed  them  to  the  "influence  of 
the  stars "  ;  but  Leonardo  da  Vinci  demanded 
"where,  in  the  hills,  are  the  stars  now  forming 
shells  of  distinct  ages  and  species  ?  And  how  can 
the  stars  explain  the  origin  of  gravel,  occurring  at 
different  heights,  and  composed  of  pebbles  rounded 
as  if  by  the  motion  of  running  water?"  Others  at- 
tributed these  forms  to  the  influence  of  a  "  plastic 
force"  in  nature.  Agricola,  a  German  miner,  con- 
ceived the  notion  that  a  ' '  certain  fatty  matter,  set 
into  fermentation  by  heat,  gave  birth  to  fossil  or- 
ganic shapes  "  ;  Fallopio  thought  that  petrified  shells 
were  generated  by  fermentation  in  the  spots  where 
they  are  found ;  or  that  they  had,  in  some  cases,  ac- 
quired their  form  from  the  ' '  tumultuous  movements 
of  terrestial  exhalations."  Olivi  thought  fossils  were 
mere  "  sports  of  nature,"  and  some  indulged  in  the 
amusing  fancy  that  they  were  "  prototypes "  or 
"models"  after  which  the  Creator  subsequently 
fashioned  the  living  creatures  of  the  sea ;  and  others 
held  that  they  were  "  created  "  just  as  we  find  them. 
The  last  opinion  I  have  heard  dogmatically  asserted 
in  America  ;  and  probably  it  still  survives. 


80        Walks  and  Talks  in  the  Geological  Field. 

When  it  became  impossible  to  resist  the  evidence 
that  these  forms  were  relics  of  the  sea,  the  theory  ob- 
tained a  foothold  that,  as  the  deluge  of  Noah  had  in- 
undated the  lands,  these  forms  must  be  the  relics  of 
that  recognized  universal  submergence.  It  required 
a  century  and  a  half  to  argue  down  this  error  ;  and, 
meantime,  the  geologists  who  did  not  subscribe  to  it, 
fell  under  the  accusation  of  "disbelieving  the  whole 
of  the  Sacred  writings."  Thus,  in  our  day,  we  stand 
at  the  outcome  of  a  contest  of  three  hundred  years. 

That  the  sea  has  covered  the  land,  and  that  shore 
lines  have  greatly  changed,  was  taught  by  Pythag- 
oras, and  afterward  by  Strabo  and  Pliny  ;  but  these 
views  were  almost  forgotten.  Many  Arabian  writers 
have  left  on  record  views  and  opinions  on  many  sub- 
jects, quite  in  advance  of  their  European  contem- 
poraries. On  this  subject  we  find  an  entertaining 
revelation  of  opinion  by  Mohammed  Kazwini,  of  the 
seventh  century  of  the  Hegira— the  close  of  the  thir- 
teenth century  of  our  era.  It  is  given  as  the  narra- 
tive of  Kidhz,  an  allegorical  personage  : 

"  I  passed  one  day  by  a  very  ancient,  and  wonder- 
fully populous  city,  and  asked  one  of  its  inhabitants 
how  long  it  had  been  founded.  '  It  is  indeed  a 
mighty  city,'  replied  he,  'we  know  not  how  long  it 
has  existed,  and  our  ancestors  were,  on  this  subject,  as 
ignorant  as  ourselves.'  Five  centuries  afterwards,  as 
I  passed  by  the  same  place,  I  could  not  perceive  the 
slightest  vestige  of  the  city.  I  demanded  of  a  peas- 
ant who  was  gathering  herbs  upon  its  former  site, 
how  long  it  had  been  destroyed.  '  In  sooth  a  strange 
question,'  replied  he,  '  the  ground  here  has  never 
been  different  from  what  you  now  behold  it.'  '  Was 


Mysterious  Forms  of  Life.  81 

there  not  of  old,'  said  I,  'a  splendid  city  here?' 
'Never,'  he  answered,  'so  far  as  we  have  seen,  and 
never  did  our  fathers  speak  to  us  of  any  such.'  On 
my  return  there  five  hundred  years  afterwards,  I 
found  the  sea  in  the  same  place,  and  on  its  shores 
were  a  party  of  fishermen,  of  whom  I  inquired  how 
long  the  land  had  been  covered  by  the  waters.  '  Is 
this  a  question,'  said  they,  'for  a  man  like  you? 
This  spot  has  always  been  what  it  is  now. '  I  again  re- 
turned five  hundred  years  afterwards,  and  the  sea  had 
disappeared.  I  inquired  of  a  man  who  stood  alone 
upon  the  spot,  how  long  ago  this  change  had  taken 
place  ;  and  he  gave  me  the  same  answer  as  I  had 
received  before.  Lastly,  on  coming  back  again,  after 
an  equal  lapse  of  time,  I  found  there  a  flourishing 
city,  more  populous  and  more  rich  in  beautiful  build- 
ings than  the  city  I  had  seen  the  first  time ;  and 
when  I  would  fain  have  informed  myself  concerning 
its  origin,  the  inhabitants  answered  me,  '  Its  rise  is 
lost  in  remote  antiquity ;  we  are  ignorant  how  long  it 
has  existed,  and  our  fathers  were  on  this  subject  as 
ignorant  as  ourselves.' " 

This  allegory  sets  forth  the  nature  of  the  modern 
scientific  conception  of  changes  in  relative  positions 
of  land  and  sea.  It  must  not,  however,  be  under- 
stood that  continents  ever  occupied  the  sites  of  the 
modern  oceans ;  though  these  oceans  once  extended 
over  all  the  lands. 

Thus  these  strata  of  sandstone,  limestone,  and  shale  what  fos- 
are  real  ancient  sea-sediments,  as  we  have  already  silsare- 
argued  ;    and  these  forms  of  life  imbedded  in  the 
strata  are  the  relics  of  the  animals  which  dwelt  in 
the  sea  while  the  sediments  were  accumulating. 


82       Walks  and  Talks  in  the  Geological  Field. 


Life  forms 
varyfrom 

'e' 


Lawof 
adap- 
tation to 
environ- 
ment. 


When  we  subject  these  relics  to  critical  examina- 
tion>  we  discover  that  their  resemblance  to  living 
forms  is  in  fundamental  characters  only.  As  to  par- 
ticular species  we  find  none,  save  in  peculiar  situa- 
tions, which  are  identical  with  living  species. 

If  the  relics  buried  in  the  rocks  present  undoubted 
divergences  from  living  forms,  it  must  be  because 
they  lived  in  other  ages,  and  under  different  physical 
conditions  from  modern  species.  As  there  is  now,  so 
there  must  always  have  been,  some  co-ordination  or 
suitability  between  the  conditions  in  which  species 
lived,  and  the  structures,  instincts,  and  capabilities  of 
the  species.  We  are  witnesses  of  this  great  prin- 
ciple —  the  adaptation  of  organism  to  environment. 
The  Hippopotamus  and  the  Elephant,  dwellers  in 
warm  climates,  are  almost  naked.  The  White  Bear 
and  the  Arctic  Fox,  dwellers  in  the  frigid  zone,  are 
densely  clad  in  fur.  The  Duck  is  impelled  by  its  in- 
stinct to  the  water  ;  so  its  feet  are  webbed  to  adapt  it 
to  movement  in  the  water.  These  co-ordinations  of 
structure  to  environment  or  surroundings,  are  every- 
where seen,  and  possess  extreme  interest. 

Now,  during  the  long  history  of  rock-accumula- 
tion, there  must  have  taken  place  very  great  changes 
in  the  conditions  of  the  world.  This  may  be  inferred 
from  the  fact  that  some  changes  are  taking  place  be- 
fore our  eyes  ;  and  also  from  the  fact,  which  we  must 
admit,  that  the  ocean  was  once  universal,  but  is  now 
interrupted  by  wide  continental  expanses  which  de- 
flect the  winds  and  the  currents  of  the  sea,  and 
modify  the  climates  of  many  regions.  It  might  thus 
be  inferred  beforehand,  that  the  populations  of  the 
world  have  shown  a  correspondence  with  the  chang- 


Mysterious  Forms  of  Life.  83 

ing  conditions  of  the  world.  If  the  physical  world 
has  improved— if  it  has  undergone  a  progression  from 
some  cruder  condition  to  the  present,  then  the  pop- 
ulations of  the  world  have  progressively  improved ; 
and  we  shall  find  the  records  of  this  improvement  in 
the  fossil  remains  of  those  populations,  as  we  hunt 
for  them  in  strata  farther  and  farther  from  the  sur- 
face— that  is,  farther  and  farther  removed  in  their 
origin  from  the  present  time. 

Now,  with  this  preparation  of  mind,  permit  me  Progress 
to  state  what  has  been  ascertained  by  studying  of  u 
the  fossils  imbedded  in  the  succession  of  strata. 
The  deepest  rocks  of  which  we  have  any  knowl- 
edge are  those  already  named  Eozoic.  They  are 
mostly  hard  and  crystalline — such  as  we  find  in  our 
innumerable  bowlders.  They  were  stratified  origi- 
nally, nevertheless ;  they  were  marine  sediments, 
and  if  any  marine  creatures  lived  at  the  time,  their 
relics  were  inclosed  in  the  sediments.  But  you  see 
how  greatly  the  sediments  have  been  changed  to 
make  of  them  granites  and  gneisses.  If  the  change 
almost  or  completely  obliterated  the  lines  of  bedding, 
it  must  also  have  destroyed  most  traces  of  the  in- 
cluded fossils.  As  a  fact,  almost  no  fossil  remains  are 
found ;  and  they  belong  to  the  very  lowest  grade 
of  animal  life.  The  ages  during  which  they  existed 
may  be  styled  the  REIGN  OF  PROTOZOANS. 

The  strata  next  above,  in  the  lower  part  of  the 
Palaeozoic  Great  System,  abound  in  the  remains  of 
marine  animals ;  but  no  traces  of  fishes  or  other 
vertebrates  have  been  found.  This  was  the  REIGN  OF 
MARINE  INVERTEBRATES.  Their  exclusive  remains 
extend  through  two  systems,  Cambrian  and  Silurian. 


84       Walks  and  Talks  in  the  Geological  Meld. 

In  the  next  higher  formations  we  detect  the  bones 
and  teeth  and  armor-plates  of  fishes.  There  were 
many  invertebrates  also,  but,  as  the  fishes  were  dom- 
inant in  rank  and  prowess,  we  designate  this  age  the 
REIGN  OF  FISHES.  The  strata  deposited  during  this 
Reign  form  the  Devonian  System.  Next  came  the 
relics  of  the  first  air-breathers  which  ever  lived.  We 
find  their  bones  resembling  those  of  modern  sala- 
manders or  amphibians,  though  often  much  more 
powerful.  This  was  the  REIGN  OP  AMPHIBIANS  ; 
and  the  corresponding  strata  are  the  Carboniferous 
System.  The  Cambrian,  Silurian,  Devonian,  and 
Carboniferous  systems  make  up  the  Palaeozoic  Great 
System. 

Next,  as  stated  in  our  last  Talk,  come  the  strata 
which  form  the  Mesozoic  Great  System.  Through 
this,  in  addition  to  relics  of  amphibians,  fishes,  and 
invertebrates,  we  find  for  the  first  time  the  bones 
and  teeth  of  reptiles.  These  creatures  offer  extraor- 
dinary interest.  Their  empire  is  known  as  the  REIGN 
OF  REPTILES.  Following  this  was  the  REIGN  OF 
MAMMALS,  since  their  bones  are  found  distrib- 
uted through  the  Ccenozoic  Great  System  of  strata. 
Lastly  came  man.  His  bones  and  works  are  con- 
fined to  the  surface  of  the  earth.  They  are  not  found 
imbedded  in  solid  rocks.  This  last  and  highest  ani- 
mal characterizes  the  REIGN  OF  MAN.  This  is  a 
grand  progression.  These  are  fundamental  concep- 
tions in  geological  science. 

As  the  reader  will  desire  frequently  to  refer  to  this 
classification  of  formation  and  of  organic  history  and 
geological  time,  I  insert  the  facts  in  the  following 
table  : 


Courses  of  the  Earth's  Masonry. 


85 


TABLE  OF  GEOLOGICAL  HISTORY. 


Great  Sys- 
tems, or 
JEons. 

Systems,  or 
Ages. 

Groups,  or 
Periods. 

Organic 
Reigns. 
(Highest 
!       fossils.) 

\    r 

Recent  ") 

QUATER- 

Champlain    V 

MAN. 

NARY... 

Glacial.         ,.    j 

C^ENOZOIC  •! 

Pliocene  1 

TERTIARY  .... 

Miocene  }• 

MAMMALS. 

Eocene  ) 

I 

Upper    Cretace-" 

oue  

CRETACEOUS 

Middle  Cretace- 
ous   

Lower    Cretace- 

REPTILES 

MESOZOIC.. 

ous. 

(and  Birds). 

JURASSIC  

Wasatch  
Nevada  

TRIASSIC  

Star  Peak  
Koipato  

Permian  

UPPER  CAR- 

Coal Measures... 

BONIFEROUS 

Conglomerate 
Measures 

AMPHIBI- 
ANS 

LOWER  CAR- 

Carboniferous     f 
Limestone 

(Land 
Animals). 

BONIFEROUS 

Catskill    (Wav- 

PALAEO- 
ZOIC.. 

DEVONIAN.... 

erlv) 

FISHES 
(Marine  Ver- 

'Chemung    ' 
Hamilton  
Corniferous  

Oriskany  

tebrates)  . 

SILURIAN  

Salina  
Niagara  
Trenton  
1.  Potsdam  

MARINE 
INVERTE- 
BRATES. 

[CAMBRIAN... 

2.  St.  John  

3.  Georgia  

EOZOIC  

(HURONIAN... 
<  LA.UREN- 

(                 TIAN...I 

/(Undivided)  ) 
t  (Undivided)  .  ...  / 

PROTgbANS. 

Divisions 
of  the 
history. 


XIII.     COURSES  OF   THE  EARTH'S  MASONRY. 

HOW  THE  FORMATIONS  ARE   ARRANGED. 

FIRST,  let  me  explain  what  is  meant  by  a  forma-  Meanings 
tion.    It  is  the  mass  of  rock  resulting  from  some  ac-  of  the 

term  for- 
tion  continued  uniformly  to  a  conclusion  or  a  pause,  mation. 

It  was  indicated  in  our  last  Talk  that  the  conditions 


Courses  of  the  Earth's  Masonry.  87 

of  the  world  must  have  changed  from  time  to  time, 
and  that  the  nature  of  the  ocean  sediments  must 
have  changed  correspondingly.  The  sediments  laid 
down  during  the  time  in  which  we  conclude  to  say 
no  change  occurred,  are  one  formation.  After  this,  a 
slight  change  would  result  in  another  formation. 
But  these  two  formations  may  much  resemble  each 
other,  though  decidedly  different  from  the  contigu- 
ous formations  above  and  below.  These  two  forma- 
tions together  may,  therefore,  be  said  to  constitute  a 
formation  in  a  larger  sense,  accumulated  during  a 
time  when  the  main  action  continued  the  same, 
though  in  subordinate  particulars  it  changed.  For- 
mation, therefore,  is  a  general  term,  not  always  sig- 
nifying the  same  amount  of  accumulation  nor  even 
the  same  range  of  diversity.  We  may  employ  it  in 
various  applications,  and  we  shall  find  it  convenient 
to  have  such  a  term.  A  system  is  a  "  formation  "  ;  a 
Great  System  is  a  "  formation "  ;  a  coal-bed  is  a 
"formation";  a  river-terrace  is  a  "formation", 
and  a  metallic  vein  is  a  "  formation."  I  must  state, 
however,  that  the  term  is  not  employed  by  all  geolo- 
gists in  this  indefinite  sense. 

Glancing  back,  now,  to  the  beginning  of  sedimen-  The  oldest 
tary  formations,  we  recognize  two  principles  which  strata  are 
must  be  accepted.    First,  the  oldest  or  lowest  sedi- 
mentary formation  must  have  rested  on  a  foundation 
not  sedimentary.     The  nature  of  that  foundation  will 
have  some  light  thrown  upon  it  after  we  have  pro- 
ceeded a  little  farther  with    our    talks.     Secondly, 
since  the  lowest  rocks  of  which  we  can  gain  any 
knowledge  are  not  such  non-sedimentary  foundation, 
we  are  unable  to  affirm  that  we  have  ever  explored  to 


88       Walks  and  Talks  in  the  Geological  Field. 

the  bottom  of  the  sedimentary  rocks.  There  may 
have  been,  underneath,  originally,  a  vast  additional 
amount  of  strata.  We  will  study  the  oldest  strata 
accessible  to  us,  and  observe  how  they  lie  in  respect 
'to  the  later  strata. 

Outcrops.  If  we  travel  over  the  surface  of  the  country,  we 
find  it  generally  overspread  by  loose  materials  which 
in  the  northern  states  are  the  so-called  Drift.  But 
here  and  there  the  bed-rocks  appear  at  the  surface. 
That  is,  they  outcrop.  The  nature  of  the  outcrop- 
ping rocks  is  various.  Sometimes  they  are  limestone, 
sometimes  sandstone,  sometimes  shale,  sometimes 
granite  or  some  other  sort  of  crystalline  rocks.  It 
seems  at  first,  as  if  everything  were  in  a  state  of  con- 
fusion. But  let  us  be  patient ;  we  shall  discover 
Arrange-  order.  We  shall  perceive  that  one  sort  of  stratum 
strata,0'  Passes  under  another,  and  perhaps  at  the  distance  of 
some  miles  comes  to  the  surface  again.  We  shall 
notice  that  a  different  stratum  or  formation  passes 
under  this,  and  then  perhaps  comes  to  the  surface 
again  at  some  point  still  more  distant — as  if  they  were 
three  wooden  dishes  in  a  pile — A,  the  largest ;  B,  the 
next  in  size,  and  C,  the  smallest.  B  goes  down  under 
(7,  and  comes  up  beyond  C.  A  goes  down  under  B, 
and  comes  up  beyond  J5,  on  the  opposite  side.  Many 
times  numerous  successive  strata  are  nested  in  each 
other  precisely  in  this  fashion.  The  lower  peninsula 
of  Michigan  is  a  good  example.  If  you  refer  to 
Synclinal  the  Table  on  page  85  you  will  see  that  the  Coal  Meas- 
basins.  ures  are  underlaid  by  the  Conglomerate  Measures, 
the  Carboniferous  Limestone,  the  Catskill  Group,  the 
Chemung  Group,  the  Hamilton  Group,  and  the  Cor- 
niferous  Group.  Each  of  these  formations  underlies 


Courses  of  the  Earth's  Masonry. 


the  peninsula  in  the  form  of  a  broad,  shallow  dish. 
The  Corniferous  Group  is  at  the  bottom.  Its  margin 
comes  to  the  surface  in  southern  Michigan.  You  see 
it  in  the  limestone  at  Monroe  and  throughout  that 
region.  Thence  it  passes  under  the  state  and  comes 
to  the  surface  again  at  Old  Mackinac  and  Cheboygan. 
Mackinac  Island,  which  we  have  talked  about,  is  of 
Corniferous  Limestone.  The  eastern  margin  of  this 
dish  is  at  London,  in  Ontario,  and  the  western  is 
under  Lake  Michigan.  A  little  nearer  the  center  of 
the  state  we  find  the  margin  of  the  next  overlying 
group — the  Hamilton.  So  the  other  groups  follow 
as  the  successively  smaller  dishes.  The  top  dish  con- 
sists of  the  Coal  Measures.  It  is  a  pretty  flat  dish, 
however,  since  the  middle  is  about  as  high  as  the 
margin. 

That  is  one  kind  of  arrangement  which  we  observe,  synclinal 
More  frequently,  however,  the  arrangement  is  more  tolds- 
like  a  pile  of  long,  broad,  thin  troughs  without  ends. 
In  this  case  you  perceive  that  each  formation  goes 
down  on  one  side  and  comes  up  on  the  opposite  side. 
But  at  the  ends,  they  may  not  appear  at  the  surface. 
Such  an  arrangement  of  strata  is  called  synclinal,  and 
the  line  along  the  middle  is  the  synclinal  axis. 

Still  another  arrangement  is   quite   as   common.  Anticlinal 
Suppose  we  turn  our  nest  of  wooden  dishes  upside  basins. 
down,  and  suppose   that  is  their  natural  position. 
They  represent  so  many  formations  still.    Then  sup- 
pose we  saw  through  the  nest  horizontally  in  such 
place  as  to  saw  off  all  the  bottoms  except  that  of  the 
smallest  dish.    It  is  done.    Now  you  see  the  edges  of 
the  formations  presenting  themselves  in  concentric 
outcrops.     Plant  yourself  on  the  inner  or  middle  for- 


90        Walks  and  Talks  in  the  Geological  Meld. 

mation.  Notice  that  this  now  underlies  all  the 
others.  This  also,  dips  toward  all  the  others,  and 
passes  under  them  out  of  sight.  Then  fix  your  atten- 
tion on  the  outcrop  of  the  next  dish.  Notice  that 
this  dips  away  from  the  first  one — the  older  one,  first 
laid  down  ;  and  that  it  dips  toward  the  newer  or 
overlying  formations.  And  so  to  the  uppermost  or 
newest — each  newer  dipping  away  from  all  the  older. 
This  arrangement  of  strata  is  common.  The  city 
of  Cincinnati  stands  on  an  upward  bulge  of  Cam- 
brian rocks.  All  around,  at  the  distance  of  some 
miles,  may  be  seen  the  outcropping  edge  of  the 
Silurian  System.  The  Silurian  strata  overlie  the 
Cambrian,  as  shown  in  the  Table,  page  85,  and  dip 
away  from  them.  Next,  a  few  miles  farther  from 
Cincinnati,  on  all  sides,  we  come  to  the  Devonian 
strata  ;  and  next,  the  Lower  Carboniferous. 
Anticlinal  Very  frequently  the  dip  is  in  opposite  directions 
folds.  along  a  line,  as  if  an  inverted  nest  of  troughs  had 
had  their  bottoms  sawed  off.  If  you  turn  an  open 
book  so  that  it  rests  on  the  table  with  the  back  up, 
then  the  leaves  are  strata  ;  their  inclination  to  the 
table  is  the  dip,  and  the  two  inclinations  in  opposite 
directions  form  an  anticlinal  structure.  If  you  keep 
the  leaves  in  the  same  position  and  turn  the  back  of 
the  book  down,  the  structure  is  synclinal.  It  is 
rather  necessary  to  understand  these  terms,  because 
we  meet  with  such  structures  so  frequently,  and  shall 
have  to  talk  about  them. 

Variations     Very  commonly,  the  dishes  and  troughs  of  which  I 
in  arrange- am  speaking  are  irregular.     A  trough,  whether  in- 
verted or  not,  may  bend,  and  change  the  course  of 
its    axis.      That  makes  it  more  difficult  to  follow, 


Courses  of  the  Earth's  Masonry.  91 

especially  as  nearly  all  the  rock  surfaces  are  concealed 
by  Drift.  Sometimes  the  trough  is  depressed  at  one 
end  ;  sometimes  at  both  ends  ;  sometimes  in  the  mid- 
dle. Again,  there  may  be  an  uplifting  of  one  or  both 
ends,  or  of  the  middle.  The  determination  of  the 
order  of  the  strata  is  often  much  complicated  by 
those  erosions  of  which  we  have  talked.  Suppose, 
for  instance,  we  have  an  anticlinal  axis,  and  suppose 
the  surface  of  the  earth  horizontal.  Then  if  a  deep 
broad  valley  were  worn  across  and  through  the  an- 
ticlinal series  of  strata,  what  sort  of  curves  would 
be  presented  by  the  cut  edges  of  the  formations  ? 
Can  you  think  them  out  ?  But  suppose  the  anticlinal 
strata  are  elevated  in  a  long  ridge  like  a  mountain, 
and  a  deep  valley  should  be  cut  down  one  side,  can 
you  picture  to  your  imagination  the  lines  which  the 
cut  edges  of  the  strata  would  trace  ?  I  think  it  would 
be  well  for  the  ingenious  reader  to  contrive  some- 
thing to  serve  as  a  model  to  illustrate  these  compli- 
cated arrangements.  A  nest  of  wooden  or  paper 
dishes  might  be  glued  together  and  sawed  and 
grooved  and  carved  into  shapes  imitating  the  con- 
figuration of  the  earth's  surface.  Even  in  level  and 
undisturbed  strata  erosions  have  created  some  com- 
plications. These  are  easily  illustrated.  Glue  to- 
gether thin  board-like  pieces  of  pine,  cherry,  oak, 
beech,  mahogany,  apple  or  other  woods,  to  represent 
strata.  Then  cut  the  pile  in  various  slopes  and 
curves,  and  notice  where  the  various  sorts-  of  wood 
outcrop.  This  represents  precisely  what  we  observe 
in  the  actual  arrangements  of  outcrops.  But  the 
Drift  covers  so  much  that  we  often  experience  diffi- 
culties in  finding  where  the  rocky  outcrops  lie. 


92        Walks  and  Talks  in  the  Geological  field. 

The  complications  in  the  structural  arrangements 
of  the  rocks  are  still  greater.  Anticlinal  dips  pass  off 
each  side  into  level  strata  or  synclinal  arrangements. 
A  synclinal  arrangement  is  often  along  the  highest 
region,  instead  of  the  lowest,  as  one  would  expect. 
On  the  contrary,  an  anticlinal  arrangement  is  often 
along  the  bottom  and  sides  of  a  valley,  instead  of  run- 
ning along  the  crest  of  a  mountain,  as  one  might  ex- 
pect. These  things  result  from  extensive  erosions. 
Again,  the  dips  sometimes  become  very  great — even 
vertical  —  and  there  may  be  difficulty  in  deciding 
which  is  the  upper  side  of  a  stratum.  Worse  than 
this,  we  sometimes  find  a  pile  of  strata  tilted  so  far 
as  to  seem  to  dip  in  the  opposite  direction.  Then  the 
older  and  lower  strata  in  fact  lie  uppermost,  and 
seem  to  be  newer.  This  inversion  of  strata  some- 
times occurs  along  the  Appalachians. 

But  there  are  some  compensations  for  all  this  con- 
fusion. The  Eozoic,  or  crystalline  rocks  are  lowest  of 
all  in  position,  and  when  they  are  in  sight  they  form 
a  landmark  from  which  we  can  estimate  upward. 
Remember,  however,  that  the  lowest  rocks — lowest  in 
geological  position— are  often  highest  in  topograph- 
ical position.  They  are  often  at  the  summits  of 
mountains,  as  in  the  Alps  and  the  Rocky  Mountains. 
The  newer  strata  then  slope  down  in  order  along 
each  side  of  the  mountain,  and  pass  under  the  plain. 

In  the  next  place,  strata  are  to  some  extent,  ar- 
ranged in  long  folds,  which  here  rise  in  a  ridge,  and 
there  disappear  under  a  synclinal.  Such  long  drawn 
forms  are  found  along  the  Laurentian  hills  in  Can- 
ada, and  along  the  Appalachians.  Here  we  catch 
sight  of  a  general  method  in  rock  arrangements. 


A   Walk  in  the  Yellowstone  Park.  93 

Still  again,  the  newest  strata  lie  along  the  Sea  and 
Gulf  shores,  and  dip  down  under  the  water.  These 
sheets  of  sediments  are  undisturbed.  Beneath  these 
are  generally  older  strata  which  have  a  correspond- 
ing dip.  These  seaward  dipping  strata  are  Csenozoic 
and  Mesozoic.  When  we  descend  to  the  Palaeozoic 
strata  we  often  find  them  considerably  folded  and 
irregular. 

In  general,  the  present  positions  of  the  strata  may  General 
be  explained  as  if  they  had  been  produced  thus :—  ^^  f 
First,  the  universal  ocean  deposited  sediments  which  positions 
hardened  into  Eozoic  rocks  which  universally  under-  of  strata 
lie.    Then  some  portion  of  the  bottom  was  uplifted 
to   daylight,    and   the   sediments   of  the    next,    or 
Palaeozoic,  JEon  were  not  universal.     Next  the  up- 
lifted regions  were  further  uplifted,  and  some  of  the 
Palaeozoic  sediments  appeared  along  the  margins  of 
the  Eozoic.    Then  followed  Mesozoic  sedimentation, 
another  uplift  of  the  same  regions ;  then  Ceenozoic 
sedimentation  and  other  uplifts.     Meanwhile  the  de- 
structive work  of  erosion  was  in  progress,  and  the 
original  shapes  of  the  uplifted  strata,  already  dis- 
guised by  many  movements,  were  further  obscured 
by  the  wearing  down  of  extensive  formations,  and 
the  obliteration  of  some.    But  of  all  this  we  shall 
catch  more  satisfactory  glimpses  hereafter. 


XIV.     A  WALK  IN  THE  YELLOWSTONE  PARK. 

THERMAL    WATERS. 

IN  THE  northwestern  corner  of  the  territory  of 
Wyoming  is  a  tract  sixty-five  miles  long  and  fifty- 


GIANT  GEYSER  IN  ACTION,  YELLOWSTONE  NATIONAL  PARK. 
(Prom  Winchell's  Geological  Studies.) 


A   Walk  in  the   Yellowstone  Park.  95 

five  miles  broad  which  has  been  reserved  by  act  of  The  Yel_ 
Congress  (March  1,  1872)  as  a  national  park  or  reser-  lowstone 
vation  "  dedicated  and  set  apart  as  a  public  park  or 
pleasuring  ground  for  the  benefit  and  enjoyment  of 
the  people."  This  was  done  on  the  recommendation 
of  the  national  geologist,  Dr.  F.  V.  Hayden.  The 
tract  on  the  north  extends  about  two  miles  into  the 
territory  of  Montana,  and  on  the  west,  two  and  a 
half  miles  into  Montana  and  Idaho.  It  lies  on  the 
great  continental  divide  at  a  mean  altitude  of  six 
thousand  feet,  and  includes  mountain  summits  ris- 
ing to  ten  and  twelve  thousand  feet — about  twice  the 
altitude  of  Mount  Washington,  and  covered,  of 
course,  with  perpetual  snow.  AVithin  the  tract  is  the 
Yellowstone  Lake,  which  lies  7,427  feet  above  sea- 
level.  Two  or  three  miles  west  of  this  is  Two  Ocean 
Pond,  lying  on  the  water-shed.  On  the  east,  the 
drainage  from  this  pond  passes  into  the  Yellowstone 
Lake  and  River,  and  thence  into  the  Missouri  and 
the  Gulf  of  Mexico.  On  the  west,  the  same  pond 
drains  into  Shoshone  Lake,  the  Snake  and  Columbia 
Rivers  and  the  Pacific  Ocean.  The  Yellowstone  and 
Madison  are  the  chief  rivers  of  the  reservation,  the 
first  flowing  west  to  form  the  Missouri,  and  the  other 
north  to  a  navigable  tributary  of  the  same.  The  up- 
per Madison  is  also  known  as  the  Firehole  River. 
Gardiner's  River  is  an  important  tributary  of  the 
Yellowstone,  flowing  north,  and  making  its  junction 
on  the  northern  boundary  of  the  Park.  Some  of  the 
loftiest  mountains  of  the  interior  overlook  the  Park 
on  all  sides.  On  the  east,  are  the  two  ranges  of  the 
Shoshone  Sierra  ;  on  the  west,  the  Gallatin  Range  ; 
on  the  south  the  Red  Mountain  Range  and  the  Pitch- 


96        Walks  and  Talks  in  the  Geological  Field. 


The 
Caflon. 


Hot 

Springs. 


stone  Plateau  ;  on  the  north,  a  belt  of  "peaks  "  rising 
ten  and  eleven  thousand  feet  high.  These  mountains, 
like  nearly  the  whole  surface  of  the  Park,  are  com- 
posed of  volcanic  rocks.  The  Yellowstone,  after  pass- 
ing two  falls,  respectively  162  and  350  feet,  flows 
through  a  canon  nine  miles  long,  which  has  been 
thus  described  : 

"For  a  mile  away,  the  sides  are  formed  of  slopes 
from  which  rise  vast  battlements,  turrets,  pinnacles, 
alone  or  in  clusters,  of  tall  conical  spires  ;  some  are  of 
basalt,  some  of  limestone  [this  is  probably  an  error]  ; 
they  rise  through  slopes  part  clay  and  part  broken 
silicates  and  limestone.  On  this  mass  of  material 
nature  has  lavished  her  wealth  of  colors  with  a 
spendthrift  hand.  The  taller  rocks  of  ruddy  browns 
or  Pompeian  red  melt  away  in  the  debris  from  which 
they  spring,  to  rich  yellows,  fading  below,  to  cool 
grays  in  exquisite  gradation.  Here  and  there  are 
rocks  of  a  red  like  claret  lees  ;  others  have  a  basis  of 
rich  ochre,  with  the  projections  of  umber  brown.  In 
places,  the  reds  are  nearly  of  a  dark  scarlet.  Here 
the  rocks  are  of  a  lovely  French  gray ;  there,  of  a 
delicate  fawn  tint,  rising  above  to  saffron,  and  melt- 
ing to  snow-white  below  ;  while  in  places,  patches  of 
vivid  green,  orange  or  black  mark  the  masses  of 
moss  and  lichen  fed  by  the  abundant  spray,  and 
forced  into  luxury  of  growth  by  the  warm  streams 
from  the  numberless  springs  issuing  from  the  walls  of 
the  canon."— LippincotV 8  Magazine,  June,  1880,  p. 
699. 

It  is  not  for  the  scenery— not  even  for  the  geology 
of  the  Park,  that  I  have  led  you  hither.  I  wish  your 
imaginations  to  be  impressed  by  the  wonderful  groups 


A   Walk  in  the  Yellowstone  Park.  97 

of  geysers  and  hot  springs  scattered  through  the 
Park.  Mr.  A.  C.  Peale,  one  of  the  United  States 
geologists,  has  described  in  the  Park  2,195  warm 
springs,  and  expresses  the  belief  that  three  thousand 
exist.  He  has  also  named  and  described  seventy-one 
geysers.  A  geyser  is  a  spring  which  periodically 
throws  up  hot  water  to  some  distance  above  the  level 
of  the  ground. 

Let  us  take  a  particular  geyser  and  note  its  situa-  Geysers> 
tion  and  the  phenomena  connected  with  its  erup- 
tions. "Old  Faithful"  geyser  is  one  of  a  group  in 
the  upper  part  of  the  valley  of  Firehole  River.  The 
external  formation  is  a  mound  or  table  of  geyserite  or  old  Faith- 
silicious  sinter— a,  whitish  mineral  composed  chiefly  ful- 
of  silica  and  water,  and  deposited  from  the  waters  of 
the  geysers.  The  mound  is  one  hundred  and  forty- 
five  feet  by  two  hundred  and  fifteen  at  base,  and 
twenty  by  fifty-four  feet  at  top.  It  rises  about  twelve 
feet  above  the  surrounding  level,  and  is  composed  of 
layers  of  deposit  arranged  in  a  succession  of  steps  that 
are  made  up  of  small  basins.  Near  the  top  these 
basins  are  beautiful,  broad,  shallow  pools,  with  pink, 
cream,  white,  brown,  and  gray  bottoms,  in  which  the 
deep  azure-tinted  water  stands  after  the  eruptions. 
The  "  chimney"  or  "  crater "  is  the  top  of  a  "  basin  " 
five  feet  deep,  at  the  bottom  of  which  is  an  irregular 
orifice,  the  head  of  the  geyser  "  tube."  The  eruption 
begins  with  some  preliminary  splashes  br  spurts — 
from  three  to  a  dozen  or  more.  These  grow  more 
powerful  for  about  four  minutes  when  jets  in  rapid 
succession  escape  with  a  roar,  and  soon  attain  the 
maximum  height.  In  a  few  seconds  later  the  column 
subsides  with  occasional  vigorous  spurts.  The  water 


98       Walks  and  Talks  in  the  Geological  Meld. 

eruption  is  followed  by  steam  which  escapes  gently 
and  soon  dies  away,  leaving  the  crater  empty.  The 
water  is  thrown  to  a  maximum  height  of  one  hun- 
dred and  fifty  feet. 

General  Sherman  thus  describes  "Old  Faithful"  : 
"We  saw  Old  Faithful  perform  at  intervals  of  sixty- 
two  to  eighty  minutes.  So  regular  are  its  periods  of 
activity  that  we  could  foretell  its  movements  within 
a  few  minutes.  Sometimes  we  stood  near  enough  to 
feel  the  hot  spray,  and  at  others,  we  sat  at  our  camp, 
three  hundred  yards  away.  Each  eruption  was  simi- 
lar, preceded  by  about  five  minutes  of  sputtering, 
and  then  would  arise  a  column  of  hot  water,  steam- 
ing and  smoking,  to  the  height  of  one  hundred  and 
twenty-five  or  one  hundred  and  thirty  feet,  the 
steam  going  a  hundred  or  more  feet  higher,  accord- 
ing to  the  state  of  the  wind.  The  whole  performance 
lasts  about  five  minutes,  when  the  column  of  water 
gradually  sinks,  and  the  spring  resumes  its  normal 
state  of  rest." 

The  The  "Giantess"  geyser,  belonging  also  to  a  group 

Giantess.  On  the  upper  Firehole,  has  an  inconspicuous  crater, 
but  is  characterized  by  magnificent  eruptions.  Mr. 
N.  P.  Langford  writes  of  it  :  "  No  water  could  be 
discovered,  but  we  could  distinctly  hear  it  gurgling 
and  boiling  at  a  great  distance  below.  Suddenly  it 
began  to  rise,  boiling  and  spluttering,  and  sending 
out  huge  masses  of  steam,  causing  a  general  stampede 
of  our  company.  When  within  about  forty  feet  of 
the  surface,  it  became  stationary,  and  we  returned  to 
look  down  upon  it.  It  was  foaming  and  surging  at  a 
terrible  rate,  occasionally  emitting  small  jets  of  hot 
water  nearly  to  the  mouth  of  the  orifice.  All  at  once 


A   Walk  in  the  Yellowstone  Park.  99 

it  seemed  seized  with  a  fearful  spasm,  and  rose  with  v 
incredible  rapidity,  hardly  affording  us  time  to  flee  to 
a  safe  distance,  when  it  burst  from  the  orifice  with 
terrific  momentum,  rising  in  a  column  the  full  size  of 
this  immense  aperture,  to  the  height  of  sixty  feet ; 
and  through  and  out  of  the  apex  of  this  vast  aqueous 
mass  five  or  six  smaller  jets  or  round  columns  of 
water,  varying  from  six  to  fifteen  inches  in  diameter, 
were  projected  to  the  marvelous  height  of  two  hun- 
dred and  fifty  feet."  This  eruption  continued  twenty 
minutes  ;  and  two  eruptions  occurred  during  twenty- 
four  hours. 

The  numerous  other  geysers  in  their  action  present  Qeyserite 
phenomena  essentially  similar  to  these.  The  min-  and 
eral  deposit  generally  forms  a  mound,  cone,  or  nozzle,  cones 
through  which  the  water  escapes.  This  varies 
greatly  in  diameter  and  height.  In  the  White  Dome 
and  White  Pyramid  geysers  it  is  twenty-five  feet 
high.  In  the  Giant  geyser  the  cone  is  ten  feet  high 
and  rests  on  a  platform  four  feet  high  and  over  three 
hundred  feet  in  diameter.  The  material  is  generally 
geyserite  ;  but  a  few  geysers  and  springs  exist  in 
which  it  is  travertine  or  calcareous  tufa,  consisting  of 
calcium  carbonate.  The  Soda  Butte,  on  the  east  of 
the  Yellowstone,  is  a  conical  mound  twenty  feet 
high,  which,  though  now  closed  at  the  top,  was  for- 
merly an  active  geyser.  It  is  composed  of  travertine, 
and  Soda  Butte  is  a  misnomer. 

The  thermal  springs  of  the  Park  have  built  up  Terraced 
mineral  deposits  of  extremely  curious  and  interest-  basins, 
ing  character.    The  Mammoth  Hot  Springs,  on  Gar- 
diner's River,  three  miles  from  its  mouth,  situated 
on  a  series  of  terraces,  present  a  fine  development  of 


100      Walks  and  Talks  in  the  Geological  Field. 

a  style  of  formation  characteristic  of  hot  springs  in 
various  parts  of  the  world.  The  waters  issue  at 
many  different  levels  along  a  slope,  and  the  calcare- 
ous deposit  takes  the  form  of  a  pile  of  tubs  so  ar- 
ranged that  the  overflow  from  one  at  a  higher  level 
falls  into  another  at  a  lower  level.  The  tubs  are  of 
various  depths  and  diameters,  and  sometimes  display 
lively  shades  of  color— greenish,  reddish,  and  yellow- 
ish. There  are  several  terraces  of  deposits  from 
which  the  water  has  disappeared  ;  and  the  evidence 
is,  generally,  that  the  thermal  energy  of  the  region 
is  diminishing. 

Geysers  in  T^e  Pnenomena  °f  hot  springs  are  well  known  in 
New  Zea-  various  parts  of  the  world.  Some  of  those  of  New 
Iceland*1  Zealand  present  close  resemblances  to  the  Mammoth 
Hot  Springs  of  Gardiner's  River.  Geysers  occur 
also,  in  New  Zealand  ;  but  the  most  celebrated  is  the 
Great  Geyser  of  Iceland.  To  impart  a  conception  of 
its  behavior  in  eruption,  the  following  description  by 
S.  Baring  Gould  is  cited :—"  Five  strokes  under 
ground  were  the  signal,  then  an  overflow,  wetting 
every  side  of  the  mound.  Presently  a  dome  of  water 
rose  in  the  center  of  the  basin  and  fell  again,  imme- 
diately to  be  followed  by  a  fresh  bell,  which  sprang 
into  the  air  full  forty  feet  high,  accompanied  by  a 
roaring  burst  of  steam.  Instantly,  the  fountain  be- 
gan to  play  with  the  utmost  violence  ;  a  column 
rushed  up  to  the  height  of  ninety  or  one  hundred 
feet,  against  the  gray  night  sky,  with  mighty  vol- 
ume of  white  steam  cloud  rolling  about  it,  and  swept 
off  by  the  breeze  to  fall  in  torrents  of  hot  rain.  Jets 
and  lines  of  water  tore  their  way  through  the  cloud, 
or  leaped  high  above  its  domed  mass.  The  earth 


102      Walks  and  Talks  in  the  Geological  Field. 

trembled  and  throbbed  during  the  explosion,  then 
the   column  sank,  started  up  again,  dropped  once 
more,  and  seemed  to  be  sucked  back  into  the  earth." 
— Pen  and  Pencil  Sketches  of  Faroe  and  Iceland. 
E    j  No  one  can  contemplate  the  phenomena  of  a  geyser 

nation  of  or  hot  spring  without  feeling  a  conviction  that  heat 
action  is  the  essential  condition.  Somewhere  within  the 
earth  is  a  repository  of  heat  sufficient  to  warm,  or 
even  to  boil,  the  water  which  rises  to  the  surface. 
Strata  whose  outcropping  edges  appear  at  the  sur- 
face, receive  rain-water  and  convey  it  along  the  dip 
to  unknown  depths.  The  water  rises  through  a  tube, 
and  in  its  lower  part  a  temperature  exists  sufficient 
to  boil  water  under  the  pressure  there  existing.  But 
details  of  the  mechanism  are  not  unanimously 
agreed  upon.  They  are  probably  somewhat  as  fol- 
lows :— Water  accumulates  in  the  geyser  pipe  upon 
the  steam  formed  in  the  lower  part  by  the  bottom 
temperature.  The  steam,  for  a  time,  is  subjected  to 
compression,  and  the  compression  increases  with  the 
continued  development  of  steam  and  accumulation  of 
water.  Finally,  the  elastic  force  becomes  sufficient 
to  lift  the  column  of  water.  The  commencement  of 
escape  now  diminishes  pressure,  and  a  large  volume 
of  steam  is  instantly  formed,  which  causes  the  vio- 
lent eruption.  The  heavy  thumps  sometimes  heard 
before  and  during  the  action  are  due  to  collapses  of 
steam  in  contact  with  the  water,  and  are  strictly  the 
same  in  principle  as  the  sharp  detonations  frequently 
heard  in  the  steam-pipes  employed  for  warming 
buildings. 


Among  the  Volcanoes.  103 


XV.     AMONG  THE  VOLCANOES. 

INDICATIONS  OF  INTERNAL,  FIRES. 

VESUVIUS  and  ^Etna  are  the  two  volcanoes  famil- 
iarly  known. to  classical  antiquity.  Let  us  make  the  tion  of 
ascent  of  Vesuvius,  taking  the  usual  route  from  Vesuvius- 
Naples.  Driving  a  couple  of  hours  down  the  coast 
to  Resi'na,  on  the  site  of  the  ancient  Herculaneum, 
we  begin  the  ascent  either  on  foot  or  on  mule  or 
horse  back.  For  thirty  minutes  we  follow  a  rough 
road  through  vineyards.  The  road  then  turns  to  the 
north  and  we  enjoy  a  lovely  view  of  the  landscape 
and  the  bay.  Here  stretch  two  dark  streams  of  cold 
lava— presenting  somewhat  the  aspect  of  enormous 
beds  of  enormous  cinders— fibrous  and  twisted  and 
wavy.  They  are  the  lava  streams  of  1858  and  1868. 
Next  appears  the  huge  lava  wall  of  1858.  In  two 
hours  from  Besina,  we  reach  the  Observatory,  2,218 
feet  above  sea-level,  erected  in  1844  for  meteorological 
and  seismic  observations.  Here  Professor  Palmieri, 
the  celebrated  vulcanologist,  is  engaged  in  making 
the  most  minute  studies  of  the  incidents  in  the  his- 
tory of  the  mountain.  From  this  station  and  the 
"  Hermitage "  just  below,  where  the  traveler  pro- 
cures refreshments,  the  view  over  the  black  and 
herbless  lava  slope  is  desolate  beyond  description. 
Soon  the  road  becomes  impracticable  for  quadrupeds. 
Crossing  the  lava  flood  of  1871,  we  now  reach  the 
Atrio  del  Cavallo,  at  the  foot  of  the  cone.  This  is 
the  valley  which  separates  the  highest  and  principal 


104     Walks  and  Talks  in  the  Geological  field. 

summit  of  the  mountain  from  Monte  Somma,  a  frag- 
ment of  an  ancient  crater  of  much  larger  size  than 
the  modern  one.  The  height  of  Vesuvius  varies 
from  3,900  to  4,300  feet.  Monte  Somma  stands  3,642 
feet.  The  slope  of  the  mountain  near  the  base  is  10°, 
while  the  active  cone  has  a  gradient  of  29°  to  30°. 
Monte  Somma  rises  almost  perpendicularly  from  the 
Atrio  del  Cavallo,  while  on  the  opposite  side,  it  slopes 
to  the  plain  at  an  angle  of  three  degrees. 

The  entire  mountain,  so  far  as  can  be  seen,  is  a  vast 
pile  of  lava,  lapilli  (stones),  sand,  and  ashes  (powder- 
like  lava),  resulting  from  a  long  succession  of  erup- 
tions. The  molten  mineral  matter  thrown  out  is 
lava.  It  escapes  from  the  regular  crater  or  bursts  out 
through  some  new  fissure  near  the  summit,  around 
which  the  erupted  materials  may  accumulate  and 
form  a  subsidiary  crater.  The  molten  lava  has  a 
temperature  above  2000°  Fah.  Often  vapor  of  water 
escapes  with  the  lava,  and  with  such  violence  as  to 
break  off  fragments  of  the  rock  forming  the  crater 
wall  and  floor,  the  larger  of  which  are  known  as 
lapilli  and  scoriae,  while  the  minuter  fragments  con- 
stitute volcanic  sand  and  ashes.  The  vapors  rise  to  a 
height  of  about  ten  thousand  feet,  and  spread  over 
the  mountain  like  a  vast  umbrella  or  Cedar  of  Leb- 
anon. Indeed,  the  height  sometimes  attained  by 
this  enormous  canopy  of  vapor  and  ashes  has  been 
shown  by  measurements  to  reach  twenty -three  thou- 
sand to  twenty-six  thousand  feet.  Enormous  quan- 
tities of  ashes  borne  upward  with  the  vapor,  give 
the  cloud  a  dark  and  angry  appearance,  and  its 
frowning  aspect  is  confirmed  by  the  flashes  of  light- 
nings which  dart  through  it.  By  night  the  vivid 


Among  the  Volcanoes.  105 

reflection  of  the  light  thrown  upward  from  the  cra- 
ter gives  the  appearance  of  terrific  flames  roaring 
from  the  summit  of  a  burning  mountain.  But  no 
proper  combustion  exists.  Often  the  condensation 
of  the  vapor  results  in  rain  which  descends  in  a  tor- 
rent. The  ashes  mingled  with  water  convert  the 
storm  into  a  deluge  of  mud.  This  rushes  down  the 
mountain  with  destructive  effects,  and  in  several  in- 
stances, whole  villages  and  even  cities  have  been 
buried  in  mud. 

A  moderate  disturbance  of  the  mountain  is  char- 
acterized by  the  ejection  of  vapors  and  stones,  ac- 
companied by  a  roar,  resembling  that  of  distant 
artillery.  More  serious  eruptions  are  accompanied  by 
loud  subterranean  noises,  earthquakes,  and  vivid 
electric  phenomena. 

History  records  a  large  number  of  Vesuvian  erup-  Examples 
tions.  According  to  Strabo,  Vesuvius  was  once  of  erup- 
covered  by  beautiful  meadows,  except  over  the  sum- 
mit, which  was  level  and  sterile.  "  It  has"  he  says, 
"  an  appearance  like  ashes,  and  shows  rugged  rocks 
of  sooty  consistency  and  color,  as  if  they  had  been 
consumed  by  fire."  At  the  same  period  the  theater 
of  volcanic  activity  was  a  few  miles  toward  the  west. 
Ischia,  Procida,  the  Solfatara  and  the  Monte  Nuovo 
were  then  active  craters.  About  A.  D.  63,  the  vol- 
canic nature  of  Vesuvius  manifested  itself ;  and  in  79 
occurred  the  terrific  eruption  which  overwhelmed 
Pompeii,  Herculaneum,  Stabise,  and  other  villages 
in  a  deluge  of  ashes  and  mud.  In  the  eruption  of 
1631,  heavy  stones  were  thrown  to  the  distance  of  15 
miles.  One  which  fell  at  the  village  of  Somma  had  a 
weight  of  fifteen  tons.  The  earth  was  convulsed  by  a 


106      Walks  and  Talks  in  the  Geological  Meld. 

violent  earthquake,  and  seven  streams  of  lava  poured 
from  the  summit,  overwhelming  Bosco,  Torre  dell' 
Annunciata,  Torre  del  Greco,  Resina  and  Portici. 
Three  thousand  persons  perished  on  the  occasion.  In 
1779  a  vast  number  of  red-hot  stones  were  hurled  to  a 
height  of  two  thousand  feet.  In  April,  1872,  after 
months  of  threatening,  the  lava  burst  forth  on  every 
side — on  the  northeast,  southwest,  and  more  par- 
ticularly at  the  Atrio  del  Cavallo,  from  which  a  huge 
stream  issued  with  such  suddenness  as  to  overtake 
and  destroy  twenty  persons  out  of  a  crowd  of  specta- 
tors gathered  to  watch  the  spectacle.  The  torrent 
descended  to  Massa  and  St.  Sebastiano,  passing  be- 
neath these  villages,  which  it  partially  destroyed, 
in  a  molten  stream  3,000  feet  wide  and  20  feet  deep. 
At  the  same  time,  amidst  terrific  thundering,  the 
crater  hurled  forth  immense  volumes  of  smoke, 
mingled  with  red-hot  stones  and  lava,  to  a  height 
of  40,000  feet. 

Mt  JEtna  M^'  ^tna  is  altogether  a  more  majestic  structure. 
It  has  a  circumference  at  base  of  one  hundred 
miles.  It  rises  10,840  feet  above  sea-level,  and  3,000 
feet  above  the  forest-limit.  The  highest  cone  is  a 
black  and  silent  waste.  The  whole  mountain,  from 
top  to  bottom,  is  a  series  of  frozen  lava-sheets  piled 
one  above  another.  Some  conception  of  the  age  of 
the  mountain  may  be  formed  from  the  fact  that 
^Etna  has  been  known  from  the  earliest  ages  as  a  vol- 
canic mountain,  and  eruptions  have  occurred,  on 
an  average,  once  in  ten  years,  yet,  within  the  historic 
period  its  bulk  and  altitude  have  not  increased  to 
a  perceptible  extent.  The  eruptions  of  ^Etna  are 
attended  by  circumstances  similar  to  those  of  Ve- 


Among  the  Volcanoes.  107 

suvius.  The  lava,  however,  does  not  escape,  in 
modern  times,  from  the  summit  crater,  but  breaks 
through  the  wall  at  some  distance  below.  In  1669, 
the  Monti  Rossi,  so-called,  were  formed,  and  27,000 
persons  were  deprived  of  all  shelter,  and  many  lives 
were  lost  in  the  descending  streams  of  lava.  In  1693, 
an  eruption  was  accompained  by  a  fearful  earthquake 
which  partially  or  totally  destroyed  forty  towns 
and  caused  a  loss  of  sixty  to  one  hundred  thousand 
lives. 

One  of  the  greatest  eruptions  of  modern  times  oc- 
curred in  1865.  After  violent  premonitory  symptoms 
two  years  previously,  when  the  loftiest  cone  of  the 
volcano  opened  on  the  side  and  emitted  a  large 
stream  of  lava,  the  wall  of  the  mountain  yielded 
to  the  pressure  of  its  molten  contents.  Some  sub- 
terranean roaring  was  first  heard ;  slight  agitations 
affected  the  whole  eastern  part  of  Sicily,  and  the 
ground  was  rent  open  for  a  mile  and  a  half  to  the 
north  of  Monte  Frumento,  one  of  the  secondary 
cones  which  rise  on  the  slope  of  JStna.  This  vom- 
ited lava  for  a  few  hours,  when,  seeming  to  be  ob- 
structed, fresh  outbursts  occurred  a  little  lower  down, 
and  six  cones  of  ejection  were  built  up.  These  and 
smaller  ones  blended  together  in  an  elevation  of 
nearly  300  feet.  Soon  the  two  upper  craters  hurled 
forth  only  lumps  of  stone  and  ashes,  while  the  lower 
poured  forth  lava.  Then  followed  the  diversified 
phenomena  of  a  prolonged  eruption,  which,  however 
interesting,  we  have  not  space  to  describe.  Of  the 
volume  of  lava  something  may  be  said. 

During  the  first  six  days,  the  quantity  of  lava  issu- 
ing from  the  fissure  of  Monte  Frumento  was  esti- 


108      Walks  and  Talks  in  the  Geological  Field. 

Voiumeof  mated  at  117  cubic  yards  a  second.  In  the  vicinity 
lava  emit-  of  the  outlet,  the  speed  of  the  current  was  not  less 
eruption16  than  twenty  feet  a  minute ;  but  lower  down  the  ve- 
locity was  diminished.  On  the  second  of  February, 
the  principal  current  had  traveled  three  miles.  It 
was  from  900  to  1,600  feet  wide  and  49  feet  deep. 
Here  it  plunged  like  a  cataract  into  a  deep  gorge. 
"  It  was  a  magnificent  spectacle,  especially  during 
the  night,  to  see  this  sheet  of  molten  matter  daz- 
zling red  like  liquid  iron,  making  its  way  in  a 
thin  layer,  from  the  heaps  of  brown  scoriae  which 
had  gradually  accumulated  above ;  then  carrying 
with  it  the  more  solid  lumps  which  dashed  one 
against  the  other  with  a  metallic  noise,  it  fell  over 
into  the  ravine  only  to  rebound  in  stars  of  fire."  In 
a  few  days  the  ravine  was  filled  and  the  lava  stood 
160  feet  deep.  From  this  the  flow  continued  east 
toward  Mascali,  filling  to  its  brink,  on  the  way,  the 
winding  gorge  of  the  dried  up  rivulet.  By  the  mid- 
dle of  February,  the  river  of  fire  was  more  than  six 
miles  long,  and  its  flow  was  more  and  more  slack- 
ened by  incasement  in  a  crust  of  cooled  material. 
Through  this,  it  continually  burst,  in  front  and  on 
the  sides,  and  new  spurts  darted  off  for  short  dis- 
tances in  various  directions,  giving  to  the  solidified 
stream  an  aspect  characteristically  rough.  Suddenly 
one  of  the  outbursts  far  up  the  stream,  resulted  in  a 
new  river,  which  flowed  toward  the  plains  of  Lingua 
grossa,  swallowing  up  thousands  of  trees.  The  de- 
structive action  was  not  much  longer  continued,  but 
months  after  the  commencement  of  the  eruption,  the 
molten  fluid  within  the  incrusted  river  continued  to 
burst  forth  in  slowly  advancing  and  overlapping  out- 


Among  the  Volcanoes.  109 

flows,  leaving  an  exterior  black  and  rough  beyond  de- 
scription. 

This  eruption  may  serve  to  illustrate  the  volume  of  other  in- 
molten  lava  sometimes  emitted  from  a  volcano.  Per-  stances»— 
haps  a  more  striking  example  of  volume  is  furnished 
by  the  volcano  of  Cosiguina,  a  hillock  about  500  feet  Cosl. 
high  on  a  promontory  to  the  south  of  the  Bay  of  euina> 
Fonseca  in  Central  America.  The  ashes  thrown  into 
the  upper  atmosphere  spread  out  in  a  dark  canopy 
several  hundred  miles  in  width.  It  covered  the 
plains  for  a  distance  of  twenty-five  miles,  with  a 
layer  of  dust  sixteen  feet  thick.  The  headland  was 
advanced  787  feet  into  the  bay.  Two  new  islands 
were  formed  from  the  ashes  and  stones.  The  wind 
carried  the  dust  westward  more  than  forty  degrees  of 
longitude,  and  a  layer  of  pumice  was  formed  at  that 
distance  which  vessels  penetrated  with  difficulty. 
On  the  east  the  fall  of  ashes  extended  to  Jamaica,  800 
miles.  The  area  covered  by  the  fall  was  one  and  a 
half  million  square  miles ;  and  the  total  volume  of 
matter  which  escaped  was  not  less  than  65^  billions 
of  cubic  yards.  The  sound  of  the  explosion  was 
heard  at  Bogota,  1,025  miles  distant.  Impenetrable 
darkness  reigned  for  forty-three  hours  throughout  the 
region  of  the  eruption. 

The  amount  of  lava   from  Kilau-e-a  in  1840  ex- 

Kilau-e-a. 
ceeded  six  billion  five  hundred  and  fifty  million  cubic 

yards.  That  from  Mauna  Loa,  in  1835,  flowed  sev- 
enty-six miles  from  the  crater.  The  volcano  of  Skap- 
tar  Jokul,  in  Iceland,  was  cleft  asunder  in  1783,  and 
gave  vent  to  two  rivers  of  fire,  each  of  which  filled 
up  a  valley  ;  one  attained  a  length  of  fifty  miles, 
with  a  breadth  of  fifteen  miles  ;  the  other  was  of  less 


110      Walks  and  Talks  in  the  Geological  Meld. 

dimensions,  but  the  depth  of  the  mass  was  in  some 
places  as  much  as  four  hundred  and  ninety-two  feet. 
The  whole  volume  of  lava  erupted  on  this  occasion 
was  not  less  than  six  hundred  and  fifty-five  billions 
of  cubic  yards — a  volume  equivalent  to  that  of  the 
whole  mass  of  Mont  Blanc. 

Many    thrilling   narratives   of  volcanic   violence 

might  be  cited;  but  these  must  serve  as  examples. 

Con-          They  demonstrate  the  existence  of  enormous  reser- 

ditionsof  voirs  of  moiten  rock  within  the  earth,  and  the  exer- 

volcanic 

action.       tion  of  such  inconceivable  forces  as  suffice  to  burst 

mountains,  to  hurl  rock-fragments  a  mile  into  the  at- 
mosphere ;  to  blow  into  atoms,  while  escaping  with 
steam  and  gases,  sufficient  matter  to  bury  thousands 
of  square  miles  in  ashes.  It  appears  that  isolated 
volcanic  cones,  like  Vesuvius,  JEtna,  and  Shasta, 
are  composed  generally  of  piles  of  ejected  materials, 
inaugurated  by  the  escape  of  matter  through  an  in- 
itial fissure.  The  volcanic  cone  is  hollow  above,  with 
a  pipe  leading  down  into  the  earth.  Through  this 
the  lava  rises  into  the  cavity.  When  the  strains 
have  sufficiently  accumulated,  the  lava  is  forced 
above  its  usual  level— sometimes  overflowing  the  lips 
of  the  crater ;  sometimes  bursting  the  walls  of  the 
mountain,  thinned  by  melting  from  within.  Some- 
times, also,  the  walls  by  internal  fusion  become  so 
much  weakened  that  the  whole  summit  falls  in, 
leaving  an  enormous  open  chasm.  Over  this  a  solid 
crust  forms  by  exposure.  Then,  in  subsequent  ages, 
this  is  pierced  by  a  new  rupture,  around  which  a 
new,  and  smaller,  cone  is  built  up,  with  the  broken 
margin  of  the  older  one  still  more  or  less  perfectly 
preserved.  So,  during  the  eruption  of  79,  the  crater 


Frozen  Seas  of  Lava.  Ill 

of  Vesuvius  collapsed,  and  the  present  crater  has 
since  grown  up,  leaving  still  on  the  north  a  vast 
rampart,  Somma,  showing  where  the  line  of  rupture 
of  the  ancient  cone  was  traced. 


XVI.    FEOZEN  SEAS  or  LAVA. 

ANCIENT  LAVAS. 

THE  spectacle  of  a  volcano  in  a  state  of  active  erup-  contrast 
tion  is  a  terrific  demonstration  of  the  forces  of  fire  between 
imprisoned  within  the  earth,  and  escaping  to  our  ism0f  the 
view  only  when  their  accumulated  strength  exceeds  present 
that  of  the  restraints  in  which  they  are  held.  These 
are  activities  of  the  present  ages  of  the  world,  and 
proofs  of  intense  heat  now  existing  within  the  cool 
exterior.  Geology  brings  to  our  notice  the  records  of 
still  vaster  and  more  terrific  operations  of  intense 
heat.  Vast  as  are  the  volumes  of  modern  eruptions, 
they  are  slight  compared  with  eruptions  of  former 
geologic  ages.  The  limited  amount  of  matter  poured 
forth  in  modern  times  cools  near  the  place  of  escape, 
and  seldom  flows  to  the  distance  of  ten  miles.  It 
accumulates,  therefore,  around  the  vent,  and  builds 
up  a  volcanic  cone.  In  earlier  times  the  molten  lava 
issued  in  such  quantity  as  to  retain  its  liquid  state 
sufficiently  long  to  flow  away  sometimes  a  hundred 
miles  or  more,  and  overspread  with  a  sea  of  fire  re- 
gions as  broad  as  states.  The  modern  volcano  ex- 
hibits, perhaps,  a  greater  explosive  energy  than  the 
ancient  one,  and  hence  it  may  disperse  greater  vol- 
umes of  ashes ;  yet  some  of  the  ancient  volcanoes, 


112      Walks  and  Talks  in  the  Geological  Field. 

near  the  beginning  of  modern   geological   history, 

have  ejected  vastly  greater  quantities  of  ashes  than 

Lava         have  been  known  to  escape  during  any  eruption  of 

fields-       historic  times.     Let  us  make  the  acquaintance  of 

some  of  the  most  remarkable  of  lava-covered  areas. 

Let  us  turn/  first,  to  what  is  probably  the  most  ex- 
Columbia  traordinary  outflow  of  lava  lying  on  the  earth's  sur- 
River  dis-  face.  A  concise,  but  comprehensive  description  has 
tricts ;  keen  furnished  by  Professor  Joseph  Leconte  :  "  Com- 
mencing in  middle  California  as  separate  streams,  in 
northern  California  it  becomes  a  flood  flowing  over 
and  completely  mantling  the  smaller  inequalities, 
and  flowing  around  the  greater  inequalities  of  sur- 
face ;  while  in  northern  Oregon  and  Washington  it 
becomes  an  absolutely  universal  flood,  beneath  which 
the  whole  original  face  of  the  country,  with  its  hills 
and  dales,  mountains  and  valleys,  lies  buried  several 
thousand  feet.  It  covers  the  greater  portion  of  north- 
ern California  and  northwestern  Nevada,  nearly  the 
whole  of  Oregon,  Washington,  and  Idaho,  and  runs 
far  into  Montana  and  British  Columbia  on  the  north. 
Its  eastern  and  southern  limits  are  not  well  known, 
but  its  extent  can  not  be  less  than  one  hundred  and 
fifty  thousand  to  two  hundred  thousand  square 
miles,  with  a  thickness  of  three  thousand  to  four 
thousand  feet  in  its  thickest  part,  where  cut  through 
by  the  Columbia  River.  In  another  place,  at  least 
seventy  miles  distant,  where  cut  into  twenty-five 
hundred  feet  deep  by  the  Des  Chutes  Eiver,  at  least 
thirty  successive  sheets  may  be  counted." 

The  Columbia  has  cut  through  the  entire  breadth 
and  depth  of  the  Cascade  range,  down  to  within  one 
hundred  feet  of  sea-level.  Here  is  a  canon  one  hun- 


Frozen  Seas  of  Lava.  113 

dred  miles  long,  with  the  summits  of  the  range  rising 
twenty-five  hundred  to  thirty-eight  hundred  feet 
above  the  river  surface.  The  entire  walls  of  the 
canon  are  composed  of  ancient  lava.  When  we  re- 
flect that  the  peaks  of  the  Cascade  range  are  simply 
results  of  erosion,  we  can  well  believe  that  the 
highest  summits  were  originally  not  less  than  four 
thousand  feet  above  the  base  of  this  astounding  lava- 
deposit. 

This  vast  and  ponderous  sheet  of  lava  appears  to 
have  flowed  through  fissures  from  the  Cascade  Moun- 
tains, and  naturally  to  have  accumulated  to  greatest 
thickness  along  that  range.  The  sheet  extends  across 
eastern  Oregon  to  the  Blue  Mountains.  From  this 
range,  also,  other,  but  less  copious,  lava  streams  were 
poured  forth. 

The  chain  of  volcanic  outbursts  continued  south- 
ward into  the  Sierra  Nevada.  The  lava  vents  here 
were  more  local  and  isolated.  The  lava,  though  enor- 
mous in  quantity,  was  less  than  in  Oregon,  and 
overspread  the  surface  less  generally.  Under  these 
circumstances,  great  volcanic  cones  were  built  up — 
such  as  Lassen,  Shasta,  Hood,  and  Eanier.  From 
Lassen's  Peak  the  sheets  of  lava  form  a  regular  slope 
to  the  Sacramento  Eiver.  Through  this  the  streams 
have  cut  their  channels  five  hundred  to  eight  hun- 
dred feet  deep. 

Nearly  all  the  so-called  Basin  Ranges  lying  east-  Basinand 
ward  of  the  Sierra  Nevada,  through  Utah  and  parts  plateau 
of  California  and  Arizona,  are  composed,  at  least  in  reglons- 
part,  of  ancient  lavas.    Through  the  Plateau  Region, 
farther   east,  lavas   are   equally  abundant.    In  the 
Sevier  Basin,  according  to  Gilbert,  the  great  Sevier 


114     Walks  and  Talks  in  the  Geological  Meld. 

fault,  or  break,  through  the  rocks,  exposes  a  maxi-, 
mum  thickness  of  two  thousand  feet.  South  of  the 
Colorado  is  a  much  larger  lava-basin,  spreading 
several  broad  lobes  over  into  New  Mexico,  the  most 
easterly  of  which  reaches  nearly  to  the  Rio  Grande. 
Its  extreme  limits  are  three  hundred  and  twenty-five 
miles  apart.  It  includes  the  San  Francisco,  Mogol- 
lon,  and  Sierra  Blanca  mountains.  This  outflow  pro- 
ceeded from  a  large  number  of  vents.  In  San  Fran- 
cisco Mountain  we  have  a  pyramid  of  compact  lava 
nearly  five  thousand  feet  high,  with  slopes  of  ten  to 
twenty  degrees. 

The  later       The  examples  cited  are  sufficient  to  impress  the  im- 

Tertiary  a  agination  and  enable  us  to  appreciate  the  magnitude 

great  vul-  °^  *ne  work  of  heat  in  the  geological  seon  not  long 

canism.      antecedent  to  the  dawn  of  modern  times.    We  mark 

the  Tertiary,  and  especially  the  later  Tertiary,  ages  as 

signalized  in  the  history  of  the  world  by  outflows  of 

molten  lava — primarily  from  fissures,  but  secondarily 

building  up  small  and  moderate  sized  cones  in  great 

abundance,  and  not  a  few  stupendous  mountain  piles 

reaching  to  eighteen  thousand  feet. 

Older  In  remote  geologic  ages  lava  eruptions  were  of  fre- 

periods  of  quent  occurrence— but  less  frequent  and  less  copious 

lvlty:    than  in  later   ages.    During  the  Triassic  Age  (see 

Table,  p.  85)  many  eruptions  of  lava  occurred,  both  in 

Europe  and  America.    The  Palisades  of  the  Hudson  ; 

Triassic,     the  cliffs  of  Meriden,  Connecticut,  and   East  and 

West  Rock,  New  Haven,  are  ancient  lavas  of  this 

age.    Much  farther  back  in   geological   history,  in 

Cambrian  Cambrian  time,  or  as  some  think  before  Cambrian 

and  pre-     time,  vast  and  repeated  outflows  of  lava  took  place 

'  which  remain  to-day  uplifted  in  Keweenaw  Point 


Frozen  Seas  of  Lava.  115 

and  lie  Royale.    The  native   copper   is  found  im- 
bedded in  these  ancient  lavas. 

A  fissure  filled  with  rock-material  solidified  from  a  Dykeg> 
state  of  fusion,  is  a  dyke.  Sometimes  the  formation 
containing  the  dyke  is  more  friable  than  the  lava, 
and  weathers  away  more  rapidly.  The  dyke  then 
projects  above  the  surface  like  a  vertical  wall.  Cer- 
tain varieties  of  lava  called  basalt  possess  the  peculiar 
property  of  assuming  a  columnar  structure  while 
cooling.  The  longer  axes  of  the  columns  are  ranged 
at  right  angles  with  the  cooling  surfaces.  Thus, 
when  the  basalt  cools  in  a  fissure,  the  columns  lie 
transversely  from  wall  to  wall.  In  most  cases,  the 
columns  are  vertical.  This  is  thought  sometimes  to 
result  from  cooling  under  the  sea  ;  but  probably  when 
a  sheet  of  basalt  rests  on  the  surface  of  the  earth,  the 
atmosphere  above  and  the  earth  below  are  cooling 
surfaces  of  the  requisite  efficiency  to  develop  vertical 
columnar  structure.  The  columnar  structure  induced 
to  an  imperfect  extent,  in  basaltic  rocks  of  lie  Royale 
may  be  conceived  as  produced  in  the  bottom  of  the 
sea ;  but  the  columnar  structure  in  the  canon  of  the 
Columbia  must  have  been  acquired  upon  the  land. 
The  columns,  in  some  cases,  rest  with  their  ends 
directly  on  a  bed  of  pebbles  and  sand  not  over  a 
hundred  feet  thick,  and  bearing  the  evidences  of  tor- 
rential action— therefore  a  shallow-water  deposit, 
while  the  columnar  basalt  is  three  thousand  five 
hundred  feet  thick.  High  cliffs  of  basaltic  columns, 
like  those  exposed  on  the  Hudson  and  Columbia 
rivers  are  often  called  palisades. 

In  some  cases  the  uprising  lavas  have  not  been  able 
to  find  their  way  to  the  surface.    Either  the  fissures 


116      Walks  and  Talks  in  the  Geological  Field. 


interca-  *n  which  they  started,  from  some  unknown  depth, 
latedbeds  never  extended  to  the  surface,  or  the  streams  lost 
laccJutes?  their  way  and  found  themselves  pent  in  the  strata, 
and  crowded  in  every  direction  in  search  of  relief. 
In  such  case  the  lavas  have  sometimes  insinuated 
themselves  laterally  between  the  strata  to  such 
extent  as  to  separate  the  strata  by  a  considerable 
interval,  without  being  able  to  escape  to  the  sur- 
face. The  result  is,  a  dome-like  elevation  of  the  sur» 
face,  forming  a  peculiar  type  of  structure  called  a 
laccolite  —  named  and  first  described  by  Mr.  G.  K. 
Gilbert.  In  many  cases,  the  arched  strata  become 
much  fissured,  and  the  lava  sheets  communicate  quite 
freely  with  each  other.  Such  laccolites  exposed  to 
the  processes  of  erosion  reveal  the  constitution  of  the 
interior.  This  subject  is  fully  illustrated  by  Mr.  Gil- 
bert in  his  memoir  on  the  Henry  Mountains  in  east 
ern  Utah. 

Erosion  River  erosions  of  vast  lava-sheets  have  resulted  in 
results  in  many  striking  forms.  As  the  most  extensive  sheets 
lava  fields.  afe  ^  reguit  of  late  geological  action,  they  generally 
rest  on  incoherent  materials—  gravel  and  sand,  as  in 
Oregon  and  California.  When  the  erosions  of  the 
streams  have  cut  through  the  lava,  and  for  some  dis- 
tance into  the  gravel,  the  less  coherent  nature  of  the 
latter  causes  an  undermining  of  the  lava-sheet.  It 
thus  projects  like  a  table-top,  beyond  the  gravel. 
When  the  erosion  cuts  the  lava-sheet  along  parallel 
lines,  it  gives  rise  to  the  forms  known  as  "table  moun- 
tains." These  are  common  in  the  volcanic  region  of 
central  France  ;  and  especially  so  in  eastern  California. 
In  Butte  County,  the  ancient  drainage  wore  channels 
stretching  westward  from  the  upland  of  the  Sierra. 


Imprisoned  Heat.  117 

These  were  subsequently  filled  by  outflows  of  lava. 
Then  in  modern  times,  a  change  of  levels  established 
drainage  from  north  to  south.  The  modern  streams, 
therefore,  have  cut  channels  across  the  ancient  ones, 
and  lava-topped  intervals  remain.  These  are  table 
mountains.  Further  south,  in  Tuolumne  County, 
the  ancient  and  the  modern  drainage  both  moved 
from  north  to  south.  The  ancient  channels,  there- 
fore, stretched  north  and  south,  and  the  lava-sheets 
which  filled  them  stretched  from  north  to  south. 
The  modern  water-courses  have  shunned  the  hard 
lava,  and  have  dug  their  channels  alongside  of  the 
lava,  in  less  consolidated  materials — gravels  or  slates. 
These  positions  were  formerly  the  elevated  banks 
of  the  streams.  Thus,  the  undisturbed,  elongated 
lava-sheets,  which  rested  on  the  bottoms  of  the  an- 
cient channels,  now  rest  on  elongated  ridges.  The 
ancient  bottoms  are  beneath  these  tables.  Over  the 
ancient  bottoms  were  distributed  the  auriferous 
gravels  from  the  mountains  ;  and  here  they  are  still 
found.  They  are  the  "deep  placers"  ;  and  are  ex- 
plored by  drifting  in  from  the  sides.  The  beds  of 
the  modern  streams,  strewn  with  auriferous  sands 
from  the  same  sources  form  the  so-called  "shallow 
placers." 


XVH.    IMPRISONED  HEAT. 

INTERNAL  CONDITION  OF  THE  EARTH. 

IN  AN  Artesian  well  the  water  is  forced  up  by 
pressure  of  other  water  standing  somewhere,  at  a 


118     Walks  and  Talks  in  the  Geological  Meld. 

higher  level,  and  freely  communicating  with  this. 
You  have  learned,  (Talk  XIII),  that  strata  often  dip 
down  from  their  place  of  outcrop  to  a  great  depth 
into  the  earth.  Suppose  a  porous  formation,  like  a 
sandstone,  thus  goes  down  from  the  surface  ;  the  rain 
which  falls  on  its  outcrop  must  soak  into  the  rock 
and  saturate  it.  This  is  then  a  water-bearing  stra- 
tum. In  descending  obliquely  it  passes  under  many 
places  ;  and  if  a  hole  should  be  bored  from  the 
surface  to  this  stratum,  the  water  would  rise  into 
it  to  the  height  of  the  place  of  outcrop.  If  the  place 
of  boring  is  lower  than  the  outcrop,  the  water 
will  rise  above  the  surface.  The  water  comes  up  with 
nearly  the  temperature  acquired  at  the  bottom  of  the 
well. 
Depth  to  The  sun's  warmth  penetrates  daily  but  a  foot  or 

which  the  two  in  summer  ;  and  at  night,  much  of  this  is  lost 

sun's  heat 

penetrates  by    radiation.     Not   all,  however,    for    the    deeper 

the  earth,  warmth  continues  to  descend  ;  and  next  day's  excess 
of  warmth  follows  this.  Thus  the  summer  heat  ac- 
cumulates, and  continues  to  descend.  It  grows  less 
and  less,  however,  and  at  fifty  feet,  can  no  longer  be 
discerned.  The  winter's  cold  also  penetrates  slowly, 
and  diminishing  in  intensity  at  every  foot,  ceases  to 
influence  the  temperature  at  the  depth  of  about  fifty 
feet.  At  this  depth  then,  the  temperature  is  constant 
the  year  round.  The  depth  of  constant  temperature 
varies,  however,  with  the  nature  of  the  climate.  If 
the  surface  fluctuations  are  excessively  great,  you  can 
understand  that  the  contrasts  must  be  felt  at  a  greater 
dePth-  In  Minnesota,  therefore,  the  depth  of  uni- 


tempera-    form  temperature  would  be  greater  than  fifty  feet.   In 
ture.          Florida,  however,  where  the  climatic  extremes  are 


Imprisoned  Heat.  119 

much  less,  the  depth  of  uniform  temperature  would 
be  less  than  fifty  feet.  The  uniform  temperature 
under  any  region  must  be  about  the  same  as  the 
mean  annual  temperature  at  the  surface. 

The  heat  of  midsummer  and  the  cold  of  midwinter 
penetrate  the  earth  at  the  rate  of  about  one  foot  per 
week.  Hence  the  cold  of  January  1st  is  felt  at  a 
depth  of  twenty-five  feet  about  July  1st ;  and  so  of 
the  cold  or  heat  of  any  other  date.  At  twenty-five 
feet  the  temperature  of  water  is  higher  in  winter  and 
lower  in  summer.  So  the  popular  opinion  about  cer- 
tain wells  is  not  entirely  unfounded. 

If,  however,  we  employ  means  to  ascertain   the  Tempera. 
temperature  at  depths  below  the  plane  of  constant  turein- 
temperature,  we  find  it  regularly  increasing  as    we  ^^f 
descend.    We  do  not  find  the  rate  of  increase  exactly  ward, 
the  same  at  different  localities,  but  the  average  is 
about  one  degree  (Fahrenheit)  for  every  fifty  or  sixty 
feet  of  descent.     The  Artesian  well  at  Charleston, 
South  Carolina,  is  1,250  feet  deep,  and  the  bottom  Obger_ 
temperature  is  87°.    As  the  mean  surface  temperature  vations  in 
is  66°,  and  the  depth  of  uniform  temperature  may  be 
assumed  at  50  feet,  the  increase  is  at  the  rate  of  57  feet 
for  one  degree.    At  Louisville,  Kentucky,  is  an  Arte- 
sian  well  2,086  feet  deep,  with  a  bottom  temperature 
of  86J°.    As  the  surface  temperature  is  55J°,  the  rate  of 
increase  is  one  degree  for  every  66  feet.    The  Belcher 
well  at  St.  Louis  with  a  depth  of  2,199  feet,  has  a 
bottom  temperature  of  73°.  4.     The  surface  temper- 
ature being  55°,  the  indicated  rate  of  increase  is  one 
degree  for  116  feet.    This  is  exceptional.    At  Colum- 
bus, Ohio,  an  Artesian  well  2,775J  feet  deep  gives  a 
bottom  temperature  of  91°  with  a  surface  mean  of  52°. 


120     Walks  and  Talks  in  the  Geological  Meld. 

This  implies  a  rate  of  increase  of  one  degree  for  every 
77  feet.    Again,  the  well  at  the  Insane  Asylum,  St. 
Louis,  is  3,843|  feet  deep  and  affords  water  at  105°, 
giving  a  rate  of  increase  of  one  degree  for  76  feet. 
dee  In   deep  mines,  the  temperature  becomes  intoler- 

mines,  able,  and  measures  have  to  be  adopted  for  the  in- 
troduction of  fresh  air  from  the  surface.  In  the  deep 
workings  on  the  celebrated  "  Comstock  Lode,"  the 
temperature  of  the  water  at  2,000  feet  is  130°.  The 
water  which  filled  the  Savage  and  Hale  and  Norcross 
mines  for  two  years,  had  a  temperature  of  157°.  At 
3,080  feet,  the  temperature  is  170°.  To  cool  the  air 
sufficiently  for  the  endurance  of  the  miners,  over 
thirty  tons  of  ice  were  consumed  daily.  [See  further, 
Talk  XXL] 

Tunnels  through  mountains   generally  attain  op- 
tunnels. 

pressive    temperatures.      The    Mont    Cenis   Tunnel 

through  the  Alps,  between  Turin  and  Chambery,  lies 
4,093  feet  below  the  surface  of  the  Pass,  or  5,251  feet 
below  the  summit  of  Mt.  Frejus,  and  is  eight  miles 
in  length.  The  rise  of  temperature  discovered  in  the 
rocks  is  about  fifty  degrees. 

Assuming  the  rate  of  increase  to  be  one  degree  for 
of  intense  60  feet  of  descent,  we  should  obtain,  in  the  latitude 

hfaT"*1  of  New  Y°rk'  heat  enou£h  to  boil  water  at  a  dePth 
of  about  9,000  feet.  At  the  depth  of  50  miles,  the 

temperature  would  be  4,600°,  which  is  far  above  the 
melting  temperature  of  ordinary  mineral  substances. 
In  this  method  of  reasoning  we  find  an  easy  explana- 
tion of  the  temperature  of  deep  waters,  and  of  the 
molten  condition  of  rocky  matter  erupted  from  vol- 
canoes. But  we  know  that  boiling  and  melting 
points,  under  the  enormous  pressure  experienced 


Imprisoned  Heat.  121 

within  the  earth,  are  materially  higher  than  at  the 
surface.  There  is  much  reason  also,  to  argue,  on 
theoretical  grounds,  that  the  rate  of  increase  of  tem- 
perature continually  diminishes  at  any  considerable 
depths.  But,  though  the  depth  may  be  quite  uncer- 
tain at  which  a  rock-melting  temperature  would  be 
reached,  we  have  the  demonstration  that  such  tem- 
perature exists  at  some  depth. 

Movements  of  temperature  beneath  the  earth's  sur- 
face  are  slow.  Many  instances  are  known  of  perma-  ice  un- 
nent  ice  preserved  in  caverns.  At  Brandon,  Ver-  m< 
mont,  permanent  frozen  gravel  exists  at  a  depth  of 
sixteen  feet.  In  the  Caucasus,  masses  of  ice  lie 
buried  permanently  in  the  moraines,  one  of  which  is 
1,500  feet  distant  from  any  glacier,  and  others  are  a 
mile  below  the  termination  of  the  glacier.  In  Si- 
beria and  in  northern  America,  the  earth  remains 
permanently  frozen  at  a  depth  of  two  or  three 
feet.  At  Yakutsk  in  eastern  Siberia,  the  earth  is 
frozen  to  a  depth  of  700  feet.  As  these  and  other 
occurrences  of  permanent  ice  are  not  attributa- 
ble to  any  climatic  influences  now  existing,  they 
must  be  the  records  and  evidences  of  more  rig- 
orous climates  in  the  past.  In  other  words,  the  cli- 
mate of  the  present  is  still  contending  with  tempera- 
tures whose  effects  are  lingering  in  protected  situa- 
tions long  after  the  climates  have  become  amelio- 
rated. It  has  been  demonstrated  that  an  ice-cap  rest- 
ing several  thousand  years  over  any  considerable 
portion  of  the  surface,  would  so  reduce  the  subjacent 
temperature  of  the  earth  that  for  many  centuries 
after  the  disappearance  of  the  ice,  a  decrease  of  tem- 
perature would  be  discovered  in  penetrating  down- 


122     Walks  and  Talks  in  the  Geological  Meld. 

ward.  Even  centuries  later,  so  much  cold  would 
still  remain  within  the  earth,  that  the  rate  of  in- 
crease of  temperature  would  be  less  than  if  the  ice- 
cap had  not  existed  ;  and  after  3,600  years,  that  rate 
would  be  only  half  the  normal  rate. 
Masses  of  lava  are  singularly  poor  conductors  of 

ing  of  lava.  neat.  A  lava  stream  has  been  found  still  hot  a  cen- 
tury after  its  eruption.  Some  years  ago  a  bed  of  ice 
was  discovered  on  the  slope  of  JEtna,  buried  beneath  a 
stream  of  lava  ;  and  from  tais  the  city  of  Catania  has 
since  obtained  supplies  of  ice.  On  Tierra  del  Fuego  ice 
and  lava  are  found  interstratifled  for  a  great  depth- 
each  winter's  snow  being  covered  by  a  new  lava- 
sheet.  In  1860  the  crater  of  the  mountain  Kutlagaya, 
in  Iceland,  hurled  out  simultaneously  into  the  air 
lumps  of  lava  and  of  ice,  all  intermingled  together. 

These  are  interesting  facts,  but  I  propose  for  them 
no  otner  use  at  present  than  to  show  some  possible 

facts.  reasons  why  the  rate  of  increase  is  unequal  at  differ- 
ent localities  or  different  depths.  We  know  that 
some  regions  have  been  overlaid  by  sheets  of  snow 
and  ice.  We  have  also  discovered  reasons  for  believ- 
ing that  our  northern  states,  as  far  as  the  bowlders 
are  distributed,  were  covered  by  continental  glaciers 
during  a  geological  period.  If  this  was  so,  it  may  be 
that  their  cooling  influence  is  still  left  within  the 
earth  ;  and  if  it  is,  the  rate  of  increase  of  tempera- 
ture as  observed  is  lower  than  it  would  be  under  nor- 
mal conditions.  A  more  rapid  rate  of  increase  im- 
plies a  thinner  crust  of  solid  matter.  But,  while 
these  considerations  must  not  be  forgotten,  it  must  be 
confessed  that  most  of  the  questions  concerning  in- 
termil  heat  are  still  imperfectly  understood. 


Imprisoned  Heat.  123 

Though  we  are  certain  intense  internal  heat  exists, 
we  neither  know  at  what  depth  it  exists,  at  what 
ratio  it  increases,  nor  what  is  its  cause  or  source. 
Nor  do  we  know  whether  the  deep  interior  is  in  a 
solid  or  a  liquid  state. 

As  to  the  cause  of  the  heat,  two  principal  theories  Theorie8 
are  held.  The  first  conceives  the  internal  heat  to  be  of  cause 
the  residual  heat  of  a  cooling  and  once  molten  globe. 
(Talks  XXXVII  and  XXXVIII.)  The  earth  is  evi-  (a) 
dently  cooling.  The  records  of  past  volcanic  action 
prove  that  heat  has  escaped  in  enormous  quantities 
from  the  interior.  Thousands  of  cubic  miles  of  mol- 
ten lava  now  solidified  over  the  surface,  imply  some 
reduction  of  the  earth's  temperature,  and  the  prob- 
lem is  one  which  might  be  solved.  The  traces  of 
former  intense  action  at  the  surface  are  retained  also 
in  enormous  rock  formations  which  have  not  been 
fused  and  reduced  to  lava,  but  have  been  softened 
and  vitrified,  and  afterward  cooled.  Then  the  daily 
radiation  of  heat  from  the  earth  exceeds  the  amount 
received  from  the  sun.  If  the  earth  is  cooling,  and 
has  for  geologic  periods  been  cooling,  it  is  not  diffi- 
cult to  admit  that  some  former  temperature  was  high 
enough  to  reduce  it  to  a  molten  condition.  If  that 
condition  existed,  the  process  of  cooling  would  result 
in  a  film  over  the  exterior,  which  would  be  the  prim- 
itive or  fire-formed  crust,  on  which  the  first  ocean 
descended,  and  the  first  sediments  accumulated, 
while  the  protected  interior  retained  a  higher  tem- 
perature. The  fusing  temperature  now  existing 
within  may  be  but  the  residuum  of  primitive  heat 
left  after  so  long  a  process  of  cooling.  This  is  one 
view. 


124     Walks  and  Talks  in  the  Geological  Field. 

(6)  Again,  it  has  been  contended  that  the  internal  heat 

results  (at  least  in  part)  from  crushing  and  friction  in 
the  crust,  produced  by  motions  and  pressures  ex- 
erted. Mallet  showed  that  the  heat  generated  in 
crushing  small  cubes  of  granite  might  become  suffi- 
cient to  cause  fusion.  We  know,  also,  that  the  cohe- 
sion of  no  substance  is  adequate  to  withstand  all 
assignable  pressures.  No  rock  has  the  requisite 
rigidity  to  resist  the  crushing  weight  of  a  mountain 
twenty  miles  high.  Whatever  movements  may  take 
place  in  the  earth's  crust,  involve  masses  so  great 
and  forces  so  enormous  that  the  resistances  of  ordi- 
nary matter  are  inconsiderable.  The  most  solid 
rocks  are  essentially  fluid  or  viscid.  Now,  such 
movements  must  necessarily  result  from  two  causes  : 
First,  a  slow  shrinkage  of  the  earth  through  loss  of 
heat ;  secondly,  the  attractions  of  the  sun  and  moon, 
which  cause  tidal  protuberances  on  the  surface  of  the 
earth,  however  rigid  it  may  be ;  and  these,  contin- 
ually shifting  their  positions,  as  the  oceanic  tides  do, 
result  in  daily  motions  adequate  to  develop  a  large 
amount  of  frictional  heat. 

But,  whatever  the  cause  of  the  internal  heat  exist- 
What  is 
the  con-     ing,  we  can  not  demonstrate  that  the  whole  interior 

dition  of  is  molten  ;  nor  that  the  earth  is  solid  to  the  core  ;  nor 
interior,  that  we  have  a  solid  core  and  a  solid  crust,  with  an 
irregular  zone  between,  in  which  the  matter  is 
molten,  or,  at  least,  in  a  plastic  state.  We  have  many 
facts  ;  we  are  building  our  theories  cautiously,  and  in 
the  meantime  we  must  all  hold  tightly  to  the  facts 
and  loosely  to  the  theories. 


The  Unstable  Land.  125 


XVIII.    THE  UNSTABLE  LAND. 

PHENOMENA  AND    CAUSES  OF  EARTHQUAKES. 

WHEN  men  feel  the  earth  beneath  their  feet  grow- 
ing unstable,  the  most  paralyzing  sense  of  insecurity 
seizes  them.  Yet  the  solid  earth  has  not  only  been 
shaken  by  throes  which  have  ingulfed  cities  and 
populations  and  mountains,  but  there  is  scarcely  a 
moment  when  its  movements  or  its  tremblings  may 
not  be  felt  by  the  delicate  means  of  research  em- 
ployed by  modern  science.  The  stability  of  the  solid 
earth  is  instability  itself. 

The  destructive  shock  lasts  but  a  few  minutes,  or  Earth- 
even    seconds.     The    successive    vibrations    which  <iuakes: 
devastated  Calabria  in  1783  were  felt  during  barely  duration, 
two  minutes.    On  the  occasion  of  the  destruction  of 
the  city  of  Lisbon,  in  1755  and  the  loss  of  60,000  lives, 
it  was  the  first  shock,  lasting  five  or  six  seconds, 
which  caused  the  greatest  damage.    As  to  extent  of 
damage,  Sicily,  in  1693,  and  Calabria,  in  1783,  have  damage, 
been  among  the  greatest  sufferers.    Each,  according 
to  best  estimates,  lost  a  hundred  thousand  lives.    In 
Syria,  Japan,   and   the   Sunda   Archipelago,  earth- 
quakes are  reported  to  have  been  attended  by  still 
greater  fatalities.    In  the  year  526,  more  than  200,000 
people  met  with  death  at  Antioch  and  the  adjacent 
towns.    The   volcanic   eruption   of  Kra-kat'o-a,    in 
August,  1883,  was  attended  by  a  sea-wave  and  earth- 
quake which,  according  to  reports,  caused  the  death 
of  twenty  thousand  persons. 


126     Walks  and  Talks  in  the  Geological  Field. 


Velocity 
of  trans- 
mission. 


Center  of 
disturb- 
ance. 


The  motions  which  constitute  an  earthquake  are 
various.  Sometimes  they  are  vertical,  either  slow  or 
rapid.  More  generally  they  are  horizontal.  In  such 
case,  they  consist  mostly  of  short,  sudden  vibrations 
which  travel  through  the  earth  at  the  rate  of  one  or 
two  thousand  feet  a  second.  The  rate  of  trans- 
mission varies  with  the  intensity  of  the  shock  and 
the  nature  of  the  rock  materials.  When  mines  of 
powder  were  exploded  near  Holyhead,  in  Wales,  the 
waves  of  disturbance  were  propagated  through  wet 
sand  at  the  rate  of  951  feet  a  second  ;  through  friable 
granite  1,283  feet,  and  through  compact  granite  1,640 
feet  a  second.  Mr.  Mallet  calculated  that  during  the 
earthquake  of  Calabria  in  1857,  the  waves  traveled 
through  the  earth  at  the  rate  of  820  feet  a  second.  It 
appears  thus,  that  the  transmission  of  the  waves  of 
disturbance  is  favored  by  the  solidity  of  the  medium. 

The  surface  movement  of  earthquake  waves  is  radi- 
ally from  a  center.  The  cause  of  the  disturbance 
must  be  regarded  as  acting  with  greatest  violence  at 
the  center,  while  the  effects  gradually  die  out,  as  the 
distance  from  the  center  increases.  But  the  distances 
to  which  the  effects  are  transmitted  are  not  equal  in 
different  directions  ;  and  this  fact  is,  undoubtedly, 
attributable  to  the  unequal  distribution  of  the  rocks. 
Generally,  the  disturbance  should  be  farther  felt  in 
the  direction  of  the  strike  of  strata,  than  in  a  direc- 
tion across  the  strata ;  since  in  the  latter  direction, 
the  waves  have  to  cross  all  the  interruptions  which 
characterize  the  stratified  condition.  So,  if  on  one 
side  of  an  earthquake  center,  the  country  is  granitic, 
and  in  the  opposite,  is  underlaid  by  Tertiary  clays 
and  sands,  the  granitic  region  will  be  most  widely 


The  Unstable  Land.  127 

and  most  severely  shaken.  It  is  not  supposable  that 
the  actual  center  of  an  earthquake  disturbance  is  at 
the  surface.  It  must  exist  at  some  considerable  depth 
beneath  the  surface.  Careful  study  of  the  directions 
indicated  by  the  effects  produced,  have  led  not  only 
to  the  determination  of  a  radial  progress  over  the 
surface,  but  to  a  center  of  disturbance,  in  each  case, 
some  miles  beneath  the  surface.  According  to  Mallet, 
the  center  of  disturbance  of  the  Calabrian  earthquake 
of  1857  was  seven  to  eight  miles  below  sea-level. 
From  this  point,  the  waves  traveled  in  every  direc- 
tion, assuming  positions  like  the  concentric  shells  of 
successively  larger  spheres.  Dr.  Oldham  found  the 
focus  of  the  great  Cachar  earthquake  of  1869  in  India, 
to  be  considerably  deeper. 

It  has  been  a  common  opinion,  from  ancient  times,  No  twlst_ 
that  earthquakes  are  sometimes  characterized  by  vor-  ln&  mov& 
tical  or  twisting  motions.    The  latest  investigations,  m 
however,  do  not  sustain  this  view.    Every  position 
assumed  by  objects  moved  can  be  explained  by  mo- 
tions of  a  rectilinear,  vibratory  character. 

Sounds  often  accompany  earthquakes,  even  when 
not  coincident  with  volcanic  eruptions.  Sometimes 
they  resemble  explosions  as  of  distant  artillery;  more 
frequently  it  is  a  rumbling  sound  as  of  heavy  ve- 
hicles moving  over  a  city  pavement.  I  have  myself 
experienced  hut  one  noteworthy  earthquake  ;  and 
that  happened  in  Michigan  and  neighboring  regions 
on  the  19th  of  September,  1884.  It  lasted  about  ten 
seconds.  The  floor  on  which  I  rested  was  very  per- 
ceptibly vibrated,  and  a  rumbling  sound  was  ex- 
tremely audible,  like  that  of  a  train  of  cars,  with  the 
beats  quite  rhythmical. 


128     Walks  and  Talks  in  the  Geological  Meld. 

Among  the  effects  of  earthquakes,  though  of  a  sec- 
earth-  ondary  character,  are  the  drying  up  of  springs,  the 
quakes,  sudden  increase  of  their  volume,  the  augmentation 
or  diminution  of  their  temperature  and  the  produc- 
tion of  muddiness  in  the  water.  Artesian  wells  are 
similarly  affected.  Sometimes  the  occasion  is  signal- 
ized by  the  escape  of  mud,  water,  gas,  or  flames. 
Occasionally,  as  in  the  Andalusian  earthquakes  of 
1884,  the  ground  is  rent  open  for  considerable  dis- 
tances. During  the  frightful  disturbances  of  Calabria 
in  1783,  the  phenomena  of  ground-ruptures  ranked 
among  the  grandest  and  most  fearful  effects  of  the 
catastrophe.  Whole  mountain  sides,  undermined  by 
water,  slid  down  in  mass,  and  tumbled  into  the 
plains  below,  covering  all  the  cultivated  ground. 
Cliffs  fell  down  in  a  body,  and  rocks  opened,  swal- 
lowing the  houses  which  stood  upon  them.  At  the 
western  base  of  the  granitic  chain  of  the  peninsula, 
the  ground  affected  by  the  shock  was  cleft  open  for  a 
length  of  more  than  eighteen  miles,  and  in  some 
places,  the  fissure  was  several  yards  in  width.  In 
another  place,  a  cleft  occurred  131  feet  deep,  over  a 
mile  long  and  32  feet  wide.  Sometimes  the  disturb- 
ances of  an  earthquake  leave  the  surface  permanently 
elevated  or  permanently  depressed.  In  one  remark- 
able instance  in  the  country  of  Cutch,  the  Great 
Runn  sank  down  over  an  extent  of  some  thousands 
of  square  miles,  so  that,  during  a  part  of  the  year,  it 
remained  inundated  by  the  sea,  and  during  another 
part  was  a  desert  without  water. 

Through  the  monumental  patience  and  industry  of 
M.  Perrey,  we  have  been  placed  in  possession  of  thou- 
sands of  statistics  of  earthquakes  between  1842  and 


The  Unstable  Land.  129 

1850.      Through  the  similar    labors  of  Mr.  Eobert  Dlstri. 
Mallet  and  his  son  John  "W.  Mallet,  we  have  been  butionof 
placed  in  possession  of  the  facts   respecting  other  q^kes 
earthquakes  between  1606   B.  C.  and  1842.     From  in  time, 
both  sources  we  have  a  record  of  six  or  seven  thou- 
sand   separate  earthquakes.    The   laborious   discus- 
sion of  this  immense  catalogue  shows  very  impor- 
tant results  respecting  the  distribution  of  earthquake 
occurrences    through   the   year.      Earthquakes   are 
found  to   occur  most    frequently  at  new   and   full 
moon,    also    more    frequently   at   perigee    than   at 
apogee  ;  also,  more  frequently  when  the  moon  is  on 
the  meridian  than  when  in  the  horizon  ;  also,  more 
frequently  in  winter  than  in  summer ;  and  finally, 
more  frequently  at  night  than  during  the  day. 

It  requires  but  little  acquaintance  with  the  phe-  varieties 
nomena  usually  ascribed  to  earthquakes,  to  discern  of  earth- 
that  they  do  not  all  belong  to  one  class.    Most  widely  quakes- 
destructive  earthquakes  are  characterized  by  vibra- 
tions of  the  earth,  and  these  alone  are  admitted  by 
Mallet  as  true  earthquakes.    These  may  be  denomi- 
nated earthquakes  of  vibration.    Other  movements  of 
the  earth  are  translatory.    The  surface  is  bodily  up- 
lifted or  depressed,  or  both  alternately.    This  may  be 
denominated  an   earthquake    of  translation.     This 
species  may  become  destructive,  especially  in  a  sec- 
ondary way,  when  occurring  either  on  land  or  under 
the  sea,  in  such  relation  to  sea-level  as  to  cause  a  rush 
of  the  sea  upon  the  land.    With  this  discrimination 
in  view,  let  us  consider  what  causes  may  be  assigned. 

The  earthquake  of  vibration  is  evidently  caused  Causes0f 
by  a  sudden  blow  or  jar ;  the  earthquake  of  transla-  earth- 
tion,  by  a  lift,  either  permanent  or  transient. 


130      Walks  and  Talks  in  the  Geological  Field. 

From  time  immemorial  earthquakes  have  been  con- 
nected in  the  minds  of  men  with  volcanic  action ; 
but  careful  study  shows  no  uniform  correlation  be- 
tween them.  Volcanic  action,  moreover,  is  too  local 
and  too  feeble.  Some,  in  modern  times,  attribute 
earthquakes  to  the  movements  of  the  molten  in- 
terior of  the  earth  acting  against  the  walls  of  its 
prison  ;  or  as  resulting  from  some  other  mechanical 
action  within  the  crust.  This  opinion  is  supported 
by  most  reputable  names — Humboldt,  Scrope,  Sir 
William  Thomson.  Movements  of  translation  are 
undoubtedly  produced  by  volcanic  forces.  Portions 
of  mountains  are  lifted  or  even  blown  away  ;  fissures 
are  caused  and  many  distinct  movements  result, 
which  are  commonly  embraced  under  earthquakes. 
Undoubtedly,  it  sometimes  happens,  also,  as  an  inci- 
dent of  volcanic  action,  that  sudden  blows,  or  violent 
explosions  occur  which  impart  vibratory  tremors  on 
a  narrow  scale,  in  character  like  those  which  some- 
times spread  over  kingdoms  and  work  vast  destruc- 
tion. But  it  can  not  be  admitted  that  earthquakes  as 
best  known — earthquakes  of  vibration— are  ascrib- 
able  to  any  volcanic  agency. 

It  may  be  mentioned,  also,  that  the  fall  of  large 
rocks,  mountain-slides,  great  explosions,  whether 
natural  or  artificial,  sometimes  occasion  genuine 
earthquake  tremors.  The  jar  of  a  train  of  freight 
cars,  or  of  a  loaded  wagon  on  the  city  pavement, 
generates  real  earthquake  tremors  ;  but  in  all  these 
cases,  on  a  scale  too  insignificant  to  be  dignified  with 
the  name. 

What  is  it,  then,  which  stands  as  the  physical 
cause  of  those  blows  or  shocks  which,  originating  at 


The  Unstable  Land.  131 

certain  foci  in  the  earth,  spread  radially  in  earth  vi- 
brations which  sometimes  level  cities  ?  I  venture  to 
affirm,  with  Mallet,  Oldham,  Schmidt,  Hottinger,  Theulti. 
and  Bocardo,  that  it  is  a  sequence  of  accumulated  mate 
strains  resulting  from  lateral  pressure  in  the  earth's  °a 
crust.  There  are  two  assignable  causes  of  enormous 
lateral  pressure.  First,  as  maintained  by  Constant 
Prgvost,  the  solid  crust  formed  around  a  cooling  mol- 
ten globe,  becoming  too  large  for  the  shrunken 
nucleus,  strives  to  adapt  itself  to  the  diminished 
interior  (molten  or  solid).  It  is,  therefore,  laterally 
pressed.  Belief  is  obtained,  in  part,  by  the  develop- 
ment of  wrinkles,  as  in  the  skin  of  a  shriveled  apple, 
and  in  part,  by  a  process  of  crushing  together.  The 
strains  are  temporarily  resisted,  but  soon  the  crust 
must  yield.  As  the  crust  is  not  homogeneous,  there 
must  be  stronger  and  weaker  portions;  The  motion 
which  results,  in  the  crisis  of  yielding,  is  accumu- 
lated in  isolated  spots.  If  the  pressure  is  a  direct  and 
simple  crushing  pressure,  then  heat  results  from  the 
crushing,  lava  is  formed  and  the  pressure  existing 
squeezes  it,  or  the  formation  of  steam  lifts  it,  to  the 
surface.  If  the  pressure  has  not  a  simple,  crushing 
tendency,  there  may  arise  a  fracture.  Then,  in  an  in- 
stant, the  strain  is  removed  ;  the  rocks  recoil,  and 
the  vibratory  motion  is  generated. 

These  lateral  strains  are  augmented  and  localized  why  most 
by  the  attractions  of  the  sun  and  moon,  which  cause  common 
real   tidal   elevations    and    subsidences,    and    thus  ana^n 
bring  the  crust  to  a  snapping  tension,  where  the  moon, 
slow   processes   of  terrestrial    contraction    had    not 
yet  reached  it.    These  tidal  strains  are  greatest  when 
the  moon  and  sun  are  nearest  the  earth,  and  also 


Relation 
to  tor- 
nadoes. 


132      Walks  and  Talks  in  the  Geological  Meld. 

when  they  act  together,  as  at  new  and  full  moon. 
To  add  another  word.  While  a  tornado  or  cyclone 
is  at  its  acme  of  violence,  the  barometer  is  low  ;  the 
pressure  of  the  atmosphere  on  the  earth  is  diminished 
at  the  spot,  and  elsewhere  correspondingly  increased  ; 
the  terrestrial  crust  must,  therefore,  tend  to  develop 
movements  of  the  nature  of  tides  ;  and  the  pre- 
disposition to  earthquake  actions  must  be  augmented. 
Observation  indicates  the  frequent  actual  coincidence 
of  earthquakes  and  cyclones.  Similarly,  a  connec- 
tion has  been  observed  between  the  pressure  of  the 
atmosphere  and  the  flow  of  springs,  and  the  dis- 
charge of  oil  or  gas  from  natural  or  artificial  open- 
ings. Many  springs  and  wells  show  a  daily  period- 
icity in  the  volume  of  the  flow,  corresponding  with 
the  diurnal  variations  in  the  pressure  and  tempera- 
ture of  the  atmosphere.  Such  facts  increase  the  pre- 
sumption that  lunar  and  solar  tidal  actions  may 
affect  the  flow  of  molten  matter,  and  also  the  dis- 
tribution of  stresses  and  movements  in  the  earth's 
crust. 


Mount 
Marcy. 


XIX.     THE  FRAMEWORK  OF  THE  MOUNTAINS. 

MOUNTAIN  STRUCTURES. 

LET  us  imagine  ourselves  standing  on  the  bald 
summit  of  Mount  Marcy  the  highest  peak  of  the 
Adirondacks,  5,400  feet  above  sea-level.  Beneath  us, 
on  every  side,  spreads  a  wilderness  of  mountain 
swells  and  intervening  wooded  valleys.  In  the  dim 
and  smoky  horizon,  in  some  directions,  we  glimpse 


The  Framework  of  the  Mountains.  133 

the  indications  of  white  villages  and  smoking  chim- 
neys, and  here  nature  still  rules  in  one  of  her  wildest 
moods. 

Notice  the  forms  of  these  summits.  How  symmet-  Form, 
rically  the  contour  sweeps  from  the  lower  and  flat- 
ter slopes  upward.  How  gracefully  these  mountain 
swellings  dissolve  in  the  green  ground  of  the  land- 
scape beneath.  Look  at  our  feet ;  the  naked  rock  lies 
cracked  and  weathered  by  the  frosts  of  unnumbered 
Winters.  The  chips  of  the  mountain  strew  the  cone 
for  eight  hundred  feet  below.  There  the  mountain 
firs,  shrinking  from  the  weather,  begin  to  appear, 
but  only  as  prostrate,  crawling,  and  stunted  shrubs. 
These  rocks  are  Eozoic.  How  hard  and  crystalline  Material 
and  stubborn  they  look.  These  black  crystals  are 
pyroxene;  the  dark,  dusky  ones  are  a  species  of 
feldspar  called  labradorite.  The  mixture  forms  a 
rock  known  as  Norite.  Polished  surfaces  present  a 
highly  pleasing  appearance.  This  rock  forms  all  the 
central  mass  of  the  mountain  under  us.  It  is  but  in- 
distinctly stratified  ;  but  we  believe  it  was  originally 
formed  from  ocean  sediments.  It  has  a  granitic  as- 
pect, and,  in  a  general  way,  we  speak  of  it  as  having 
a  granitic  character. 

It  is  not  an  easy  matter  to  travel  down  the  slope 
of  this  summit,  over  the  loose  crags,  down  into  the 
border  of  the  forest,  through  the  forest  to  the  foot 
of  the  mountain,  into  the  lumber  camps,  down  to  the 
clearings,  amongst  the  log  cabins,  on  to  the  village, 
over  the  highway  and  the  railroad,  and  ascertain 
at  every  step,  what  kind  of  rock  underlies.  There  is 
too  much  rock-rubbish,  too  much  soil,  too  dense 
an  undergrowth. 


134      Walks  and  Talks  in  the  Geological  Meld. 

structure  When  we  descend  from  the  summit  of  Mt.  Marcy, 
we  come,  part  way  down  the  slope,  to  massive 
gneisses.  They  rise  up  into  view  from  the  lower 
levels.  They  present  their  crumbling  and  hoary  out- 
crops looking  up  toward  the  summit  of  the  moun- 
tain, as  if  ambitious  to  attain  the  apex,  but  wearied 
and  wasted,  and  arrested  by  the  way.  Here  they  lie, 
resting  on  their  granitic  bed.  All  around  the  moun- 
tain, the  upward  looking  outcrops  of  gneisses  occur. 
The  head  of  Mt.  Marcy  rises  above  the  heavy  blan- 
keting of  gneiss. 

Down  the  mountain  to  the  lower  levels  we  con- 
tinue our  exploration.  Here  the  exposed  outcrop- 
pings  of  other  gneisses  are  seen  enwrapping  the 
lower  and  older  ones  ;  here  schists— hornblendic  and 
micaceous — come  into  view  in  succession,  overlying 
the  beds  whose  outcrops  are  higher  up,  and  all  dip- 
ping steeply  down  ;  here  is  a  thick  bed  of  crystalline 
marble,  green-stained  with  intermingled  serpentine. 
Here  are  beds  of  iron-ore,  and  other  schists  and  con- 
glomerates, all  dipping  still  down  the  slope,  and  each 
new  one  in  succession  reposing  on  the  top  of  the  last. 

Should  we  descend  the  slopes  of  the  Adirondacks 
in  a  hundred  directions,  such  would  be  the  succes- 
sion of  the  formations — such,  at  least,  the  plan  of 
the  mountain  structure,  though  the  particular  kinds 
of  gneiss  or  of  schist  would  vary  on  different  sides. 
Let  us  think  about  the  nature  of  this  arrangement. 
It  looks  as  if  the  gneiss  and  schists  had  once  lain 
horizontal,  and  the  head  of  Mt.  Marcy,  and  the  heads 
of  the  other  mountain  giants,  had  been  thrust  up 
through — bursting  the  sheets  of  gneiss  and  schist — 
parting  them  to  the  east  and  west,  the  north  and 


The  Framework  of  the  Mountains.  135 

eouth— continuing  to  push  up  a  mile  toward  the  sky, 
and  leaving  the  parted  borders  of  the  bedded  rocks 
far  down  the  slopes— separated  by  the  diameter  of 
the  mountain  mass.1  It  looks  so — and  that  is  the 
ground  for  the  inference  that  it  was  so.  We  have 
been  contemplating  forces  possessed  of  the  ability  to 
perform  such  a  piece  of  work.  Kra-kat'-o-a  was  split 
from  bottom  to  top  in  1882.  If  volcanic  forces  should 
prove  inadequate,  we  can  invoke  other  forces.  We 
will  invoke  them.  But  let  us  see  further  what  there 
is  to  summon  them  to  accomplish.  » 

We  are  strolling  upon  the  flanks  of  the  Adiron-  Thegeol- 
dacks.    We  are  now  on  the  borders  of  civilization.  ogyofthe 

surround- 

Mt.  Marcy  looks  down  on  us  from  the  cold  blue  sky  ing  coun- 
against  which  his  profile  is  printed.  We  tread  now  try- 
on  another  soil.  Here  are  massive  cliffs  of  sandstone. 
If  we  wander  around  by  the  east,  we  may  trace  the 
Au  Sable  toward  its  source.  We  find  it  roaring 
through  a  cleft  in  a  gray  sandstone  with  perpendicu- 
lar walls  one  hundred  feet  high,  and  along  a  chasm 
which  splits  the  formation  for  a  distance  of  two 
miles.  This  is  the  chasm  of  the  Au  Sable.  But  see, 
this  sandstone  is  not  a  metamorphic  rock.  It  lies 
above  all  the  gneisses  and  schists.  It  is  not  so 
steeply  inclined.  Evidently  it  is  not  within  the 
Eozoic  Great  System  ;  it  is  Palaeozoic.  Follow  it  as 
it  stretches  under  the  country  to  the  eastward.  It 
extends  to  Lake  Champlain.  It  reappears  on  the 
Vermont  side,  and  continues  to  the  Green  Moun- 
tains. If  we  carry  our  observations  to  the  north 
flanks  of  the  Adirondacks,  there  too,  we  find  this 

iCompare  this  with  the  second  paragraph  on  p.  142.    The  two 
ideas  are  not  exactly  the  same.    F.  S. 


136      Walks  and  Talks  in  the  Geological  Meld. 


How  the 
Adiron- 


were 
made. 


The  Lau- 

rentide 

Hills 


sandstone.  The  charming  village  of  Potsdam  is 
built  on  this  sandstone— a  classical  spot  which  has 
given  its  name  to  a  formation  that  reappears  in  all 
countries.  This  sandstone  spreads  out  horizontally 
to  the  St.  Lawrence  River.  If  we  examine  the  Adi- 
rondack slope  on  the  westj  the  Potsdam  sandstone  is 
found  in  its  place,  and  even  limestones  come  in  suc- 
cession, in  higher  geological  positions  above  the 
sandstone.  On  the  south  we  still  find  the  sand- 
stone. 

The  appearance  now  is,  that  after  the  granite 
center  had  burst  through  the  gneisses,  and  all  these 
rocks  were  standing  at  a  level  somewhat  lower  than 
at  present,  the  ocean  still  covered  the  flanks  now 
overlaid  by  the  Potsdam  sandstone,  and  on  the  bot- 
tom of  that  ocean  the  sands  were  spread  which  were 
destined  to  become  consolidated  as  sandstone ;  then, 
after  this,  there  was  a  farther  uplift  of  the  Adiron- 
dack mass,  bringing  the  Potsdam  sands  above  sea- 
level,  around  their  border,  and  giving  them  also  a 
tilt,  while  the  gneisses  received  an  increased  tilt.  So 
the  granitic  center  of  the  Adirondacks  was  at  first  a 
small  island  ;  then,  by  further  upheavals,  the  island 
was  enlarged  progressively  on  all  its  borders. 

Now  let  us  proceed  across  the  St.  Lawrence  valley. 
Here  we  find  horizontal  Potsdam  sandstone  stretch- 
ing up  and  down  the  valley  ;  and  above  this  a  thick 
series  of  limestones.  Continuing  toward  the  Lau- 
rentide  Hills,  we  see  the  horizontal  strata  turning  up 
gently.  We  ascend  a  gradual  slope,  and  by  and  by, 
the  limestones  end.  A  steeper  ascent  is  still  under- 
laid by  the  Potsdam  sandstone.  Here  now,  is  the 
end  of  the  sandstone  and  we  step  on  schists  and 


The  Framework  o/  the  Mountains.  137 

gneisses  and  crystalline  limestones,  each  rising  from 
under  the  preceding,  until  we  reach  granitic  rocks, 
which  continue  to  the  summit  of  the  ridge.  Then 
passing  still  northward,  we  meet  various  formations 
like  those  seen  in  ascending  the  ridge,  but  in  the  in- 
verse order.  In  fact,  the  nature  of  the  rocks,  their 
altitudes  and  their  order  of  arrangement  are  exactly 
like  what  we  found  in  descending  the  Adirondacks. 

The  Laurentian,  therefore,  has  the  same  constitu-  repeat  the 
tion  as  the  Adirondacks.    It  is  an  elongated  eleva-  story, 
tion,  however,  instead  of  a  cluster  of  peaks.    It  pre- 
sents an  anticlinal  structure.    The  oldest  or  bottom 
rocks  are  in  the  center,  and  rise  to  the  highest  alti- 
tude.   The  rocks  geologically  higher  in  position  at- 
tain to  successively  lower  and  lower  altitudes ;  they 
dip  down  on  each  side  of  the  granitic  axis,  like  a 
series  of  planks  leaning  against  a  stone  wall. 

This  is  the  general  plan  of  a  mountain  of  upheaval.  Mountains 
We  find  the  same  in  the  Blue  Ridge,  in  the  ranges  ofup- 
of  the  Eocky  Mountains  and  many  others  of  the 
great  ranges  of  the  country.     Mountains,  therefore, 
exist  as  long  folds  of  the  earth's  crust ;  and  very  gen- 
erally, where  one  fold  exists,  two  or  three  others 
exist  parallel  with  this,  as  in  the  Appalachians. 

It  will  be  borne  in  mind  always,  that  every  oro-  secondary 
graphic  or  mountain  feature  has  undergone  a  great  mountain 
amount  of  alteration.    The  summits  of  the  moun- 
tains have  been  much  lowered.    The  strata  enwrap- 
ping their  flanks  have  been  cut  back  ;  they  stretch  to 
less  distances  than  formerly  toward  the  summit.    In 
many  cases,  indeed,  we  have  room  to  conjecture  that 
they  extended  originally  over  the  summit,  and  have 
been  worn  away  in  the  course  of  ages,   uncovering 


138      Walks  and  Talks  in  the  Geological  Field. 

the  granitic  nucleus  only  in  later  geological  time. 
In  some  cases,  the  erosion  of  parallel  and  contigu- 
ous mountain  crests  has  proceeded  so  far  that  the 
summits  are  lower  than  the  valleys  between  them. 
The  valleys  then  become  the  mountains,  and  in  place 
of  the  original  mountains  are  valleys  of  erosion.  So 
we  sometimes  find  a  synclinal  structure  in  moun- 
tains, and  an  anticlinal  structure  under  valleys. 
Sometimes  we  find  a  river  cutting  through  a  moun- 
tain from  side  to  side  and  from  top  to  bottom.  The 
Green  River  in  Wyoming,  affords  a  striking  example. 
It  cuts  through  the  15,000  feet  of  the  altitude  of  the 
Uinta  Mountains.  It  seems  quite  evident  that  the 
river  was  here  before  the  mountain.  The  mountain 
rose  gradually  under  the  river,  and  as  it  rose,  the 
river  sawed  its  gap  to  the  bottom,  and  the  walls  of 
the  gap  were  left  to  rise  precipitously  on  each  side. 
Other  mountains  have  been  rent  by  fissures.  These 
generally  run  lengthwise  of  the  range — most  fre- 
quently along  the  center.  When  they  exist,  the 
strata  on  one  side  are  generally  found  depressed  be- 
low the  level  of  the  corresponding  strata  on  the  other 
side.  Such  a  case  is  a  fault.  In  the  Appalachians 
are  faults  of  five  thousand  to  twenty  thousand  feet. 
Faults.  A  greater  one  cuts  through  the  Uintas.  The  Sierra 
Nevada,  for  three  hundred  miles,  has  been  split 
lengthwise  along  the  middle,  and  the  eastern  half, 
for  a  large  part  of  the  distance,  has  gone  down  three 
thousand  to  ten  thousand  feet.  So  the  west  half 
the  Wahsatch  went  down  forty  thousand  feet  for  a 
length  of  at  least  one  hundred  miles. 

Mountains      Of  mountains  of  relief,  like  the  Catskills  and  the 
o/reiief.      Cumberland    Table    Land,    something    has    already 


Hoiv  the  Mountain  Framework  is  Beared.     139 

been  said  in  Talk  IX,  and  nothing  more  is  necessary 
here.  Mountains  composed  of  volcanic  accumula- 
tions are  mentioned  in  Talks  XV  and  XVI. 


XX.     How   THE  MOUNTAIN   FRAMEWORK   is 

BEAKED. 
MOUNTAIN  FORMATION. 

BY  WHAT  machinery  were  these  mountain  masses 
upraised?    By  what  motive  force  was  it  actuated  ? 
Generations  past,  which  had  witnessed  the   tre-  old 

mendous  power  of  Vesuvius  and  ^Etna,  thought  the  theoriesof 

mountain 
volcano  adequate  for  the  production  both  of  earth-  making. 

quakes  and  mountains.  It  was  steam  and  gases  try- 
ing to  find  vent,  they  said,  which  shook  the  ground 
and  bulged  the  terrestrial  crust  into  mountain  sa- 
liences. They  had  seen  mountain  caps  blown  off, 
and  mountains  cracked  open  ;  they  had  even  seen 
Sabrina  and  Graham's  Island  and  many  JSgsean 
islands  lifted  from  the  bottom  of  the  sea,  and  sus- 
tained at  an  elevation  of  some  hundreds  of  feet. 
Were  not  these  efforts  at  mountain-making  and  un- 
making ?  Had  it  not  been  ascertained,  too,  in  more 
recent  times,  that  Vesuvius  and  ^Etna,  with  all  their 
loftiness  and  massiveness  are  mere  piles  of  stuff 
brought  up  by  volcanoes,  and  built  by  volcanic  ac- 
tion into  mountain  forms  ? 

Yes,  the  reasoning  is  good  for  a  certain  class  of  Vulcan- 
mountains.    But  the  Adirondacks  are  not  a  pile  of  ^J^^ 
lava  ;    nor   the  Laurentides  ;   nor  the  Appalachian  to  Adiron- 
ranges  ;  nor  the  White  Mountains  ;  nor  the  Eockies.  dacks>ete- 


140      Walks  and  Talks  in  the  Geological  Field. 

Here  has  been  lifting  to  which  all  volcanic  work 
bears  a  very  feeble  comparison.  If  JStna  and  Hood 
are  piles  of  volcanic  debris,  consider  how  small  a  part 
was  lifted  at  once.  The  ascent  of  the  mountain  ma- 
terials has  been  like  that  of  wheat  in  the  grain  ele- 
vator— little  at  a  time,  but  much  in  the  aggregate. 
Look  at  the  Adirondacks,  on  the  other  hand — here  is 
a  vast  framework  ;  all  the  parts  were  formed  and  ad- 
justed together  before  the  uplift ;  and  when  the  time 
arrived,  the  total  mass  was  raised  in  one  stupendous 
mechanical  effort.  We  must  seek  a  greater  power 
than  the  volcano. 

Contrac-        ^  *s  not  a  trivial  problem.    It  has  puzzled  the  most 

tionofthe  expert  of  brains.    But  I  think  you  have  made  the 

crust  the    Acquaintance  of  forces  and  modes  of  action  which 

great         furnish  us  a  real  clew  to  the  mechanism  of  moun- 

cause.         tain-making.    Your  attention  has  been  directed  to 

many  indications  of  the  presence  and  action  of  heat 

in  the  earth.    You  have  even  reached  the  inference 

that  the  earth  is  a  cooling  globe.     [But  see  further  in 

Talks  XXXVII  and  XXXVIII.]     Now,  you  have 

often  witnessed  the  power  of  heat.    When  it  enters  a 

solid  or  liquid,  expansion  takes  place,  and  the  power 

of  expansion    surpasses    human  control.    When  it 

leaves  a  body  contraction  ensues,  and  the  strength  of 

this  tendency  can  not  be  resisted  by  any  means  in 

our  power.    Loss  of  heat  is  regularly  attended  by 

contraction. 

Now,  ever  since  Leibnitz,  two  hundred  years  ago, 
enunciated  his  theory  of  a  once  molten  earth,  geog- 
iiostic  students  have  been  considering  what  must  be 
the  natural  course  of  events  in  the  cooling  of  such  a 
globe.  Constant  Prgvost  advanced  a  suggestion 


Hoiv  the  Mountain  Framework  is  Reared.    141 

sound  in  theory  and  fruitful  in  consequences.  That 
molten  globe,  he  said,  must  have  become  incrusted. 
By  degrees  the  crust  would  thicken,  and  the  trans- 
mission of  heat  from  the  interior  would  be  retarded. 
By  and  by,  the  radiation  of  heat  from  the  exterior 
would  become  diminished  to  such  an  extent  as  to  just 
equal  the  heat  received  at  the  surface  by  transmission 
through  the  crust.  That  is,  a  constant  temperature 
would  exist  at  the  surface  of  the  earth — a  constant 
temperature  at  the  mid-zone  in  the  crust.  But  the 
interior  would  still  continue  to  lose  heat  through  the 
crust,  though  the  crust  retained  a  uniform  tempera- 
ture. If  the  interior  did  not  supply  heat  to  the  crust, 
the  latter  would  grow  colder. 
So  the  interior,  in  consequence  of  loss  of  heat  Asthein- 

would  contract;  but  the  crust,  losing  no  more  than  teriorcon- 

tracts,  the 
it  receives,  would  not  contract.    That  is,  the  crust  crust 

would  become  too  large  for  the  shrunken  nucleus.  wrinkles- 
What  would  result  ?  Do  you  conceive  that  the  crust 
would  rest  raised  above  the  nucleus,  leaving  vacant, " 
or  even  steam-filled  spaces  between  the  two?  Re- 
member the  enormous  weight  of  the  atmosphere — 
fourteen  pounds  on  every  square  inch.  Remember 
the  enormous  weight  of  the  crust,  and  the  utter  im- 
possibility of  its  sustaining  the  strain  of  bulging  over 
a  vacuum  of  one,  ten,  or  a  hundred  miles.  Assuredly, 
the  crust  must  settle  down  as  fast  as  the  molten  nu- 
cleus grows  smaller. 

But  now,  in  settling  down,  its  circumference  must  The  force 
constantly  become  less.    How  can  its  circumference  jfr, 
be  made  less  ?    Only  by  squeezing  together  from  all 
directions.    There  must  be  a  lateral  pressure  experi- 
enced at  every  point.    It  arises  from  the  weight  of 


142      Walks  and  Talks  in  the  Geological  Meld. 

the  crust,  and  is  proportional  to  the  weight  of  the 
crust.  If  the  crust  is  thus  subjected  everywhere  to 
an  enormous  lateral  pressure,  then,  either  the  parts 
of  the  crust  must  be  mashed  together,  producing  a 
thickening  in  proportion  to  diminution  of  circum- 
ference ;  or  else,  if  the  crust  is  too  solid  to  be  crushed, 
it  will  wrinkle — just  as  the  skin  of  an  apple  is 
wrinkled,  when  the  pulp  within  shrinks  through 
the  evaporation  of  juice. 
The  Now,  suppose  that  stage  of  things  has  been  reached. 

wrinkles  gome  wrinkles  have  made  their  appearance  on  the  sur- 
are  moun- 
tains, face  of  the  earth.  They  are  the  beginnings  of  moun- 
tains. If  ocean  waters  rest  now  on  the  earth's  sur- 
face, they  may,  indeed,  totally  cover  these  wrinkles— 
but  they  are  the  germs  of  mountains,  nevertheless. 
As  long  as  the  earth's  interior  continues  to  lose  heat 
and  contract,  so  long  wrinkling  tendencies  will  exist. 
But,  after  a  set  of  wrinkles  has  been  first  developed, 
the  wrinkling  tendency  afterward  finds  relief  in  the 
same  wrinkles— in  the  enlargement  of  the  first 
wrinkles.  The  power  to  enlarge  and  further  elevate 
the  old  wrinkles  will  be  attained  before  the  power  to 
initiate  wrinkles  in  new  places.  In  this  way  the 
germinal  mountains  would  grow.  In  this  way,  the 
first  uplifted  masses  would  afterward  be  uplifted 
higher,  as  new  relief  had  to  be  sought.  Did  we  not 
observe  the  successive  stages  of  uplift  in  our  study  of 
the  Adirondacks  ? 

Relation        There  is  no  volcanic  uplifting  here.     It  is  true, 
ofvuican-  however,  we  may  get  volcanic  phenomena.      The 

ism  to 

mountain  crust  presses  with  enormous  weight  on  the  molten 

making,     ocean.     Compare  it  with  a  field  of  ice  a  mile  square 

and    three  feet  thick,  floating  on  a  lake.     If  you 


How  the  Mountain  Framework  is  Reared.     143 

make  a  hole  through  the  ice,  the  water  rises  in  the 
hole,  nearly  to  the  surface  of  the  ice.  If  the  hole 
is  suddenly  made,  the  water  may  rise  with  such 
velocity  that  its  momentum  will  carry  it  quite  to  the 
surface,  or  over  the  surface.  This  is  like  an  outflow 
of  volcanic  matter  through  a  fissured  crust.  Suppose 
a  great  number  of  piles  of  ice  be  heaped  up  on  this 
ice  field  in  various  parts.  Then,  if  a  hole  be  pierced 
through,  the  water  will  rise  with  increased  likelihood 
to  overflow.  Now  these  piles  of  ice  exert  an  effect 
similar  to  that  of  upraised  wrinkles  in  the  crust.  So 
it  appears  that  volcanoes  may  be  an  incident  of 
the  earth's  contraction,  as  before  stated,  and  that 
mountain-making  may  be  another  incident  of  the 
same.  But  there  is  more  to  be  said.  In  many  places 
must  occur  some  crushing  together.  In  the  moun- 
tain folds  where  the  internal  constitution  and  firm- 
ness have  been  strained  by  flexures,  there  must  be 
weakness  ;  and  there  must  occur  some  of  that  mash- 
ing together  which  develops  heat,  independently  of 
any  supply  from  the  molten  interior.  It  is  quite 
intelligible,  therefore,  that  a  mountain  wrinkle  or 
fold  is  a  zone  where  heat  must  be  generated,  even 
if  lava  is  not  produced,  and  does  not  escape  from 
within.  Along  a  mountain  fold,  in  other  words,  is  a 
zone  where  the  rocks  must  be  subjected  to  that  bak- 
ing or  semifusion  in  connection  with  water,  which 
produces  the  changes  called  metamorphism. 

It  would  not  be  proper  to  leave  the  subject    in  why  do 
this  state,  though  you  have  already  the  gist  of  the  mountain 
theory  of  mountain  making.    All  our  great  moun-  trend 
tains   exist   as    long    ranges— mostly    as   groups  of  mainly 
ranges,   and    the    prevailing  direction   of  mountain  south? 


144      Walks  and  Talks  in  the  Geological  field. 


Effect  of 

tidal 

action. 


trends  is  approximately  north  and  south.  Now, 
when  we  consider  the  wrinkles  on  the  skin  of  a 
withered  apple,  we  find  them  short,  and  having 
also,  no  uniformity  of  trend.  The  analogy,  is  im- 
perfect. There  must  have  been  some  other  cause  than 
uniform  shrinkage  to  develop  the  actual  mountain 
folds. 

Let  us  glance  back  over  the  early  history  of  the 
earth.  They  tell  us  it  once  revolved  much  more 
rapidly  on  its  axis  than  at  present.  It  is  not  difficult 
to  understand  why  its  rotation  has  been  retarded,  but 
we  will  pass  that  by.  If  the  rotation  has  slackened, 
then  the  equatorial  protuberance  has  diminished. 
That  is,  the  equatorial  circumference  has  been  short- 
ened more  than  the  polar  ;  and  consequently  there 
has  been  more  lateral  pressure  around  the  equatorial 
region.  That  pressure  too  was  exerted  east  and  west, 
and  that  was  just  the  direction  which  would  give 
to  the  wrinkles  a  north  and  south  trend,  and  a  con- 
siderable elongation.  Besides  this,  there  was  a  pow- 
erful tidal  attraction  exerted  by  the  moon  (see  also 
Talk  XXXVIII).  That  body  was  then  much  nearer 
the  earth  than  now,  and  exerted  important  influences 
on  the  earth.  In  our  times,  it  raises  the  ocean  and 
the  whole  hemisphere  in  a  tidal  swell ;  then,  though 
no  ocean  existed,  the  tidal  swell  was  raised  with  the 
forming  film  over  its  surface.  But  the  rise  of  the 
swell  was  not  instantaneous ;  it  reached  its  height 
after  the  moon  had  passed  the  meridian  to  the  west, 
and  the  moon  acting  on  it  from  that  position,  pulled 
the  apex  slightly  westward,  and  thus  established 
changed  conditions  in  the  crust  which  necessarily 
had  a  north  and  south  trend,  and  contributed  some- 


Down  in  a  Mine.  145 


thing  to  give  the  wrinkles,  which  were  then  forming, 
the  north  and  south  axes  which  we  see  in  mountain 
ranges. 
Another  peculiarity  of  mountains  is  the  greater  Mountain 

thickness  of  the  formations  and  the  greater  proper-  ranses 

and  sedi- 
tion of  fragmental  strata.    This  has  led  some  to  con-  men- 

ceive  that  the  materials  of  mountains  were  accumu-  tation- 
lated  in  the  bottom  of  the  sea,  in  situations  to  which 
ocean  currents  brought  unusual  quantities  of  coarse 
deposits  from  neighboring  continental  shores.  It  is 
supposed  that  these  sediments  depressed  the  bottom 
and  thus  preserved  such  depths  as  would  continue  to 
invite  the  currents  to  a  continuance  of  their  work, 
until  the  mountain  mass  was  completed.  The  sink- 
ing of  the  great  synclinal  must  have  subjected  the 
materials  to  the  metamorphic  influence  of  internal 
heat,  even  without  any  crushing  together.  Probably, 
in  this  state  of  things,  metamorphism  resulted  from 
both  causes.  Then  in  due  time,  the  synclinal  was  up- 
raised, with  additional  crushing,  and  the  mountain 
was  completed. 

These  are  but  glimpses  of  the  theory  of  mountain- 
making  ;  but  I  hope  they  will  stimulate  you  to  fur- 
ther study.  Let  me  recommend  the  re-reading  of 
this  Talk,  after  Talk  XXXVIII. 


XXI.    DOWN  IN  A  MINE. 

MODES  OF  OCCURRENCE  OF  THE  METALS. 

WHO  HAS  not  heard  of  the  Comstock  Lode  ?    Who  Descrip- 
has  not  read  something  about  the  hundreds  of  millions  Jjom 
of  gold  and  silver  extracted  from  its  deep  depositories?  Lode. 


146      Walks  and  Talks  in  the  Geological  Field. 

What  is  the  Comstock  Lode  ?  It  is  a  body  of  gold- 
and-silver-bearing  mineral  matter  lying  in  the  Vir- 
ginia range,  a  spur  of  the  Sierra  Nevada,  about  25 
or  30  miles  east  of  the  Sierra  crest.  The  range  trends 
a  little  east  of  north,  and  the  lode  appears  to  be  the 
filling  of  an  imperfect  fissure  four  or  five  miles  long 
— the  principal  part  of  which  is  about  10,000  feet. 
The  fissure  extends  into  the  mountain  with  an  east- 
ward dip  varying  from  33°  to  45°.  At  the  north  end 
it  divides  into  three  or  more  diverging  and  somewhat 
irregular  branches,  and  at  the  south  end  it  termi- 
nates in  two  branches.  The  fissure  has,  at  its  broad- 
est part,  along  the  middle,  a  width  of  about  600  feet, 
which  becomes  1,400  feet  when  measured  along  the 
sloping  surface ;  and  it  narrows  toward  each  end. 
The  lode  also  narrows  downward,  and  at  about  1,800 
feet  vertically,  has  a  thickness  of  about  120  feet. 
The  part  above  this  seems  to  be  formed  from  two 
fissures  and  the  wedge-shaped  mass  of  "  country 
rock  "  included  between  them.  This  wedge  of  coun- 
try rock  was  cut  off  from  the  east  side,  where  the  rock 
is  diabase — that  is,  composed  of  grains  of  augite  and 
a  plagioclase  feldspar.  On  the  west  side,  the  country 
rock  is  diorite— that  is,  composed  of  hornblende  and 
a  plagioclase  feldspar.  In  miners'  language  a  frag- 
ment of  country  rock  included  in  a  lode  is  a  "horse." 
The  fissure  along  each  side  of  this  enormous  "  horse  " 
is  filled  chiefly  with  quartz.  The  east  wall  in  this 
case,  is  the  "  hanging  wall,"  and  the  west  is  the 
"  foot- wall."  The  hanging  wall  is  much  decom- 
posed, and  the  decomposition  extends  through  the 
diabase  for  five  thousand  feet. 
The  contents  of  the  lode  are  somewhat  miscel- 


Down  in  a  Mine.  147 

laneously  disposed.  Besides  the  great  prismatic 
horse  just  mentioned,  are  many  smaller  fragments 
of  country  rock,  together  with  clay,  quartz  and  sil- 
ver-bearing minerals.  Most  of  the  ore  contains  both 
silver  and  gold,  but  the  proportions  of  the  two  metals 
vary  in  different  parts  of  the  lode.  From  the  whole 
lode  the  yield  of  gold  has  been  43  per  cent  and  of  sil- 
ver 57  per  cent.  The  richest  quartz  lies  nearest  the 
hanging  wall.  A  mass  of  ore  rich  enough  to  pay  for 
working  is  styled  a  "bonanza."  An  ore  must  afford 
fifteen  or  twenty  dollars  a  ton  to  pay.  The  cele- 
brated "  great  bonanza"  averaged  $80  to  the  ton.  It 
was  composed  of  crushed  quartz,  including  frag- 
ments of  country  rock,  and  carried  a  few  hard,  nar- 
row, vein-like  seams  of  very  rich  black  ores  ;  while 
nearly  the  whole  mass  of  the  crushed  or  "  sugar 
quartz  "  was  impregnated  to  a  moderate  extent,  with 
native  gold  and  stephanite,  which  is  an  arsenical 
sulphide  of  silver  known  sometimes  as  brittle  silver 
glance.  Even  the  country  rock  was  also  charged 
with  these  ores. 

It  would  not  be  proper  to  enter  further  into  partic-  Mode  of 
ulars  of  this  kind.  But  glance  a  moment  at  the 
mechanical  operations.  Perhaps  you  think  the 
miners  attacked  the  wonderful  lode  at  its  outcrops, 
and  followed  it  down  on  a  slope  into  the  earth.  Not 
at  all.  As  soon  as  this  method  of  exploration  had 
revealed  the  position  and  promise  of  the  lode,  great 
capitalists  laid  out  the  work  according  to  methods 
sanctioned  by  centuries  of  experience  in  other  coun- 
tries. Going  some  hundreds  of  feet  to  the  east  of  the 
lode,  a  vertical  shaft  would  be  sunk  until  the  lode 
was  struck.  At  frequent  intervals,  horizontal  pas- 


148     Walks  and  Talks  in  the  Geological  Field. 

sages  were  excavated  westward  to  the  lode,  and 
through  the  lode  to  the  foot  wall.  From  these, 
other  passages  or  galleries  were  excavated  along  the 
lode.  From  these  numerous  galleries,  the  various 
ore-bodies  were  discovered  and  worked  out,  within 
the  limits  of  the  claim.  There  is  a  large  number  of 
claims  or  properties  along  the  lode,  and  there  are 
twenty-four  shafts  sunken  on  the  east.  In  course  of 
time,  the  various  mining  operations  have  been 
brought  into  some  degree  of  concert  and  system. 
Without  this,  the  difficulties  of  the  deep  exploration 
of  the  lode  would  have  been  insuperable.  The  coun- 
try has  thus  become  honey-combed  to  a  depth  of  3,000 
feet.  The  total  length  of  the  galleries  driven  ex- 
ceeds 150  miles. 

Obstacles.  Heat  and  water  have  presented  obstacles  most 
formidable.  The  high  temperature  of  the  rock  and  of 

i.  Heat,  the  water  escaping  from  it  is  very  extraordinary.  On 
the  3,000  foot  level  of  the  Comstock,  floods  of  water 
have  entered  the  mines  at  170°.  Water  at  this 
temperature  will  cook  food,  and  will  destroy  the 
human  epidermis.  A  partial  immersion  in  it  is  there- 
fore fatal.  The  atmosphere,  as  a  consequence,  is  not 
only  intolerably  hot,  but  is  saturated  with  vapor. 
From  prolonged  exposure  to  these  unnatural  condi- 
tions, many  miners  have  lost  their  lives.  In  the 
Savage  mine,  in  1879,  the  miners  struck  a  hot  spring 
having  a  temperature  of  157°,  and  the  incline  was 
filled  with  scalding  vapor  ;  picks  could  only  be  hand- 
led with  gloves,  and  rags  soaked  in  ice-water  were 
wrapped  about  the  iron  drills.  Occasionally,  per- 
spiration would  cease,  the  miner  would  begin  to  talk 
in  a  rambling  fashion,  and  his  death  would  soon 


Down  in  a  Mine. 


ensue,  unless  removed  by  his  comrades  to  a  place 
of  relief.  The  conditions  of  mining  are  greatly 
ameliorated  by  most  efficient  ventilation  through  the 
150  miles  of  galleries  and  the  shafts.  Still,  the  air 
leaves  the  mines  nearly  saturated  with  aqueous 
vapor,  and  at  an  average  temperature  of  92°. 

The  increase  of  downward  temperature  here  greatly  Abnormal 
exceeds  the  general  average.  In  one  shaft  at  100  feet,  tempera- 
the  temperature  was  50°  ;  at  200  feet,  55°  ;  at  500  feet, 
68° ;  at  800  feet,  76°  ;  at  845  feet,  80°  ;  at  1,100  feet,  92°. 
In  another  shaft,  at  1,500  feet  the  temperature  was 
105°;  at  1,600  feet,  107°  ;  at  1,700  feet,  108°  ;  at  1,800  feet, 
111°  ;  at  1,900  feet,  112° ;  at  2,000  feet,  113° ;  at  2,280 
feet,  121°.  Mr.  Church,  who  investigated  this  subject 
very  carefully,  estimated  the  mean  temperature  on 
the  2,000  foot  level,  at  130°.  The  water  at  170°,  with 
which  the  Gold  Hill  mines  were  flooded  in  the 
winter  of  1880-1,  entered  on  the  3,000  foot  level, 
and  was  struck  at  3,080  feet.  All  the  data  together  in- 
dicate an  increase  of  temperature  of  one  degree  for 
28  feet  of  depth.  This  abnormal  increase  appears 
confined  to  the  vicinity  of  the  lode.  The  great  Sutro 
Tunnel,  which  approaches  the  east  wall  at  a  depth  of 
1,900  feet,  indicates  a  great  increase  of  temperature  in 
approaching  the  wall.  At  the  distance  of  128  feet,  the 
temperature  is  110°  ;  at  1,048  feet,  108°  ;  at  2,052  feet, 
96°  ;  at  3,651  feet,  89°  ;  at  5,008  feet,  87°  ;  at  7,175  feet, 
85°  ;  at  9,512  feet,  83°  ;  at  10,849  feet,  79°.  This  great 
increase  of  temperature  cannot  be  attributed  to  the 
increase  in  depth  of  the  tunnel  below  the  earth's  sur- 
face. The  extraordinary  temperature,  therefore,  is 
a  phenomenon  of  the  lode.  It  appears  to  rise  from 
some  greater  depth,  and  the  indications  point  to 


150     Walks  and  Talks  in  the  Geological  Meld. 

ascending  water  as  the  probable  agent  in  bringing 
up  the  heat  from  a  deeper  region.  It  acts,  therefore, 
like  an  enormous  hot  spring.  Thirty  miles  away 
is  the  Sierra  Nevada  range,  and  from  the  altitude 
of  perpetual  snow,  the  eastward  dipping  strata  de- 
scend into  the  earth  for  a  great  depth.  The  waters 
which  accompany  them  reaching  the  deep  portion 
of  the  Comstock  Lode,  their  course  is  in  part  arrested 
by  the  impervious  clays.  When  reached  therefore  by 
the  mining  operations,  the  relief  of  pressure  causes 
them  to  rise  from  depths  much  below  the  bottom 
of  the  works. 

2.  Waters.  The  waters  just  mentioned  constitute  the  second 
powerful  obstacle  to  mining  on  the  lode.  In  the 
deeper  works,  the  volume  has  assumed  portentous 
proportions.  The  water  was  originally  pumped  to 
the  surface  through  the  vertical  shafts.  Steam-pumps 
of  ever  increasing  capacity,  however,  proved  suc- 
cessively inadequate  to  the  demand.  Hence,  the  dar- 
The  sutro  ing  enterprise  of  Adolf  Sutro  conceived  the  tunnel 
Tunnel.  which  bears  his  name,  and  which  through  thirteen 
years  of  opposition,  he  fought  to  successful  comple- 
tion in  1878,  at  a  cost  of  two  million  dollars.  The 
outlet  of  the  tunnel  is  20,000  feet  from  the  east  wall  of 
the  lode.  From  the  entrance,  a  lateral  branch  is  ex- 
tended north  along  the  lode  4,403  feet  (to  October, 
1880),  and  another  lateral,  southward,  4,114  feet.  The 
tunnel  is  seven  feet  in  height,  and  eight  feet  in  width 
in  the  clear,  with  a  grade,  of  one  inch  in  100  feet.  In 
the  bottom  is  a  drainage  channel  five  feet  wide  and 
three  and  one-half  feet  deep.  After  the  mining  com- 
panies began  pumping  water  into  the  tunnel,  over 
three  and  a  half  million  gallons  were  discharged 


Down  in  a  Mine.  151 

every  twenty-four  hours.  During  1880,  the  aggregate 
was  over  a  billion  and  a  quarter  gallons,  and  it  was 
estimated  that  double  this  quantity  would  be  dis- 
charged when  connection  should  be  made  with  all 
the  mines.  The  temperature  of  the  mixed  water  en- 
tering the  drain  is  137°,  and  its  temperature  at  the 
mouth  is  118°.  Little  use  is  made  at  present  of  this 
stream  of  water,  amazing  equally  for  volume  and  for 
temperature.  It  is  apparent,  however,  that  this  vast 
stream  of  hot  water  possesses  capabilities  of  useful- 
ness which  American  enterprise  will  not  permit  to 
run  to  waste  indefinitely. 

During  twenty  years,  up  to  1881,  the  bullion  yield  of  Yield  of 
the  Comstock  Lode  had  been  $306,000,000.  Since  1874,  the  lode- 
business  on  the  lode  has  been  much  depressed. 

Investigations  have  been  made  for  the  purpose  source  of 
of  ascertaining  the  source  of  the  precious  metals  in  the 
the  lode.  Mr.  George  F.  Becker  has  shown  the  pres- 
ence of  gold  and  silver  in  the  unaltered  diabase  rock 
on  the  east  of  the  lode,  and  demonstrated  it  practi- 
cally absent  from  that  part  contiguous  to  the  lode 
which  has  undergone  decomposition.  It  results  from 
his  studies,  that  after  the  region  had  been  shattered 
by  earthquake  disturbances,  floods  of  heated  waters 
rose  through  the  rocks,  carrying  carbonic  and  sul- 
phydric  acids,  and  saturating  the  east  country,  dis- 
solving out  silica  and  metallic  salts,  and  redeposit- 
ing  them  again  in  the  spaces  comparatively  open. 
He  finds  by  calculation  that  the  total  metal  taken 
from  the  lode  is  not  in  excess  of  that  originally  con- 
tained in  the  diabase  on  the  east,  within  the  region 
now  occupied  by  the  decomposed  rock. 

This  explanation  will  apply  to  the  accumulation  of 


152      Walks  and  Talks  in  the  Geological  Field. 


True 
reins. 


The  Eu- 
reka dis- 
trict. 


ore  in  veins  of  a  more  typical  character.  The  Corn- 
stock  Lode  can  scarcely  be  called  a  "true  vein"  in 
the  accepted  sense.  A  vein  proper  is  a  fissure  ex- 
tending to  a  great  depth  in  the  earth,  and  having 
generally  a  considerable  longitudinal  extent,  with 
a  width  varying  from  a  few  inches  to  several 
feet,  and  with  its  contents  often  arranged  in  lay- 
ers upon  each  of  the  two  walls,  in  the  same  order 
from  the  wall.  Each  of  these  layers  is  called  a 
comb,  and  the  whole  is  styled  the  gangue.  The 
metalliferous  layer  is  the  ore.  Many  of  the  most 
important  Old  World  mines  are  based  on  true  veins. 
Many,  also,  in  America ;  but  in  many  of  the  most 
celebrated  mines,  the  mode  of  occurrence  of  the  ore 
is  different. 

In  the  Eureka  mining  district,  in  Central  Nevada, 
we  have  a  regular  succession  of  strata  consisting  of 
limestones,  shales,  and  quartzites,  ranging  from  the 
Cambrian  to  the  lower  Carboniferous,  but  mingled 
with  porphyritic  eruptions  and  all  shattered  by  a  pro- 
cess of  faulting.  The  silver-bearing  lead  ore  is  found 
imbedded  in  the  lower  Carboniferous  Limestone, 
within  masses  of  hydrous  iron  oxide.  The  deposits 
are  discovered  and  worked  out  by  a  regular  system 
of  mining  through  shafts  and  galleries  ;  though,  in 
the  works  of  the  Richmond  company,  these  formal- 
ities are  discarded,  and  the  deposits  are  reached  and 
worked  out  by  the  shortest  cuts.  It  can  scarcely  be 
said  that  the  ore  occurs  here  in  veins.  It  lies  in 
masses  having  cavities  above.  Its  origin  is  from  be- 
low ;  but  the  stratified  rocks  have  not  served  as  its 
source.  But  the  quartz-porphyry  of  the  region,  by 
leaching  with  hot  alkaline  waters,  may  have  afforded 


The  King  of  Metals.  153 

the  ore  ;  and  this  is  thought  by  Curtis  to  have  been 
its  probable  source. 

The  silver-bearing  galena  of  Leadville,  in  Colorado,  Leadville 
according  to  Emmons,  has  a  similar  mode  of  occur- 
rence. The  deposit  of  the  silver-bearing  minerals 
took  place  in  the  lowest  member  of  the  Carboniferous 
System.  They  were  derived  from  circulating  waters, 
which  obtained  them  in  passing  through  eruptive 
rocks.  How  introduced  into  the  eruptive  rocks  is  a 
matter  for  speculation. 

In  the  lead-producing  region  of  Wisconsin,  Iowa,  Lead  of 
and  Illinois,  the  galena  and  blende  occur  as  a  lining  Wiscon" 
on  the  walls  of  cavities  or  caverns  in  a  magnesian 
limestone  of  upper  Cambrian  age.    In  Missouri,  sim- 
ilar cavities  in  the  Lower  Magnesian  Limestone,  of 
lower  Cambrian  age,  are  found  lined  with  galena  and 
quartz. 


XXII.    THE  KING  OF  METALS. 

IRON  AND  ITS   GEOLOGY. 

THE  most  useful  of  the  metals  is  most  abundant  Vaiue  of 
and  most  universal.  Iron  is  found  in  formations  of  iron- 
every  age,  from  the  Laurentian  of  the  Eozoic  to  the 
Quaternary  and  even  the  bogs  which  are  forming  in 
the  age  of  man.  It  may  be  of  interest  to  point  out 
the  fact  that  we  find  iron  most  useful,  not  because 
most  abundant  and  most  accessible,  but  because  its 
properties  give  it  preeminent  superiority.  Gold  and 
silver  and  platinum  are  wanting  in  the  hardness  and 
rigidity  which  suit  iron  to  many  of  its  most  impor- 
tant adaptations.  Neither  of  these  metals  could  be 


154     Walks  and  Talks  in  the  Geological  Field. 

made  into  useful  rails  for  the  steam  train  to  move  on. 
Neither  would  furnish  a  tool  having  the  edge  and 
temper  of  fine  cutlery 

How  con-       Iron  is  almost  universally  disseminated,  as  a  con- 
centrated: stituent,  through  the  rocks  and  minerals.    It  some- 
times imparts  a  black,  and  sometimes  a  red  or  yellow- 
ish  color;   and   many  times  its   presence  is  unan- 
nounced by  any  color.    This  red  soil  which,  in  some 
regions,    prevails  extensively,    is   colored   by   iron. 
This  red  sandstone  is  colored  by  iron,  this  red  shale, 
this  red  brick— like  this  red  rust  on  the  stove-pipe. 
This  yellow  precipitate  in  the  bottom  of  the  stream 
is  the  same  with  water  in  combination.    These  are 
oxides.    They  hold  all  the  oxygen  which  the  iron 
can  take,  and  hence  they  are  called  peroxides.    But 
the  yellow  oxide   holds  water   also,  and   hence   is 
Bog  iron     known  as  a  hydrated  peroxide.    Now  follow  this  hy- 
ore<  drated  peroxide — this   yellow  ochre — down    to    the 

bog  which  the  water  saturates.  Here  is  black  muck 
—a  fine  peaty  material — but  it  is  colored  and  charged 
with  this  ocherous  deposit.  After  some  years,  the 
peaty  matter  decays,  and  disappears,  to  some  extent. 
Then  we  see  the  iron  compound  aggregated  and  com- 
pacted in  irregular  masses.  It  has  now  become  bog 
iron  ore.  It  is  a  kind  of  limonite,  so-called.  It  can  now 
be  smelted  in  a  furnace  and  the  pure  iron  extracted. 

If  this  swamp  should  be  sunken  below  sea-level, 
Limonite.  an<^  heavy  layers  of  marine  sediments  spread  over  it, 
the  bog  ore  would  be  compressed  into  a  compact 
stratum.  Then  if  all  these  formations  should  be  con- 
verted to  solid  rock,  our  bed  of  bog  ore  would  be  ex- 
actly such  a  bed  of  limonite  as  we  actually  find  in 
some  situations  deep  in  the  rocks.  It  would  be  an 


The  King  of  Metals.  155 

old  fossil  swamp.  But  suppose  some  thousands  of 
feet  of  sediments  should  be  piled  over  it.  Then  the 
heat  of  the  earth's  interior  would  come  up  and  bake 
the  ore-bed.  Very  likely  the  water  would  be  ex- 
pelled from  our  limonite,  and  it  would  become  simply  H£ematite 
a  peroxide— it  would  assume  a  red  color — it  would  be 
hcematite,  which  means  blood-red  ore.  Now  such  beds 
of  haematite  form  many  of  our  most  valuable  depos- 
its of  iron  ore.  Much  of  the  ore  in  the  Lake  Supe- 
rior region  is  of  this  kind — also  in  northern  New 
York  and  in  other  regions.  But  if  this  old  haematite 
is  left  exposed  to  water  for  some  years — if  the  bed 
becomes  soaked  with  water,  it  changes  back  to  limo- 
nite ;  it  becomes  yellow  and  somewhat  soft.  The 
miners  sometimes  call  it  "soft  haematite."  It  is 
easily  quarried  and  easily  smelted,  and  everybody 
likes  it — though  ton  for  ton  of  ore,  it  contains  less 
iron  than  hard  or  true  haematite. 

I  do  not  assert  that  all  limonite  and  haematite  have 
come  into  existence  in  this  way.  But  I  am  sure  this 
theory  is  highly  plausible  for  some  beds  of  iron  ore. 
But  now,  I  have  noticed  iron  ores  in  such  situations 
that  perhaps  a  different  explanation  is  more  reason- 
able. I  have  seen  great  masses  of  iron  ores  inclosed 
in  the  midst  of  great  stratified  formations.  The  ore- 
masses  are  huge  lenticular  accumulations — some- 
times of  great  purity,  sometimes  mixed  with  rocky 
matter,  sometimes  bounded  abruptly,  and  sometimes 
blending  gradually  with  the  contiguous  strata.  The 
ores  occur  in  this  way  at  Lake  Superior.  Such 
masses  of  ore  are  almost  always  in  crystalline  meta- 
morphic  rocks.  They  have  been  heated — probably 
subjected  to  the  action  of  hot  water. 


156      Walks  and  Talks  in  the  Geological  Field. 

Magnetite.  There  is  another  species  of  iron  ore  very  commonly 
associated  with  these.  It  is  magnetite.  This  is  com- 
posed partly  of  peroxide  of  iron  and  partly  of  prot- 
oxide of  iron — that  is,  iron  with  only  one  proportion 
of  oxygen  combined  with  it.  Magnetite  is  richer, 
therefore,  than  haematite — ton  for  ton  of  ore  it  con- 
tains more  iron.  While  powdered  haematite  is  red, 
and  powdered  limonite,  brownish  yellow,  powdered 
magnetite  is  black.  Magnetite  attracts  the  magnetic 
needle.  "Lodestone"  is  magnetite— so-called,  prob- 
ably, because  it  leads  by  its  attraction.  Now,  magne- 
tite is  often  found  in  great  imbedded  masses,  like 
haematite,  and  is  regarded  one  of  the  most  desirable 
of  ores.  Often  haematite  and  magnetite  are  mingled 
together  in  the  same  bed ;  and  the  indication  is, 
that  one  is  capable  of  conversion  into  the  other. 
Dissemi-  ^e  °^en  find,  also,  considerable  formations  in 
nated  iron:  which  much  iron  ore  exists  in  a  disseminated  state, 
concenbe  imParting  a  highly  ferruginous  character  to  the  rock, 
trated  in  but  constituting  only  a  very  "lean  ore."  It  may  be 
thanra!ayS  a  hsematitic  quartzite  or  a  silicious  haematite.  We  find 
bog  ore?  all  stages  of  transition  from  pure  ore  masses  to  sim- 
ple rock.  The  theory  is  often  suggested  to  me  by  the 
conditions  under  which  these  metamorphic  ores  ex- 
ist, that  they  are  simply  accumulations  of  ores  gath- 
ered together  from  wide  contiguous  regions  in  the 
rock.  It  seems  settled  that  ores  of  lead,  zinc,  and  sil- 
ver are  thus  eliminated  from  the  country  rock,  as  was 
explained  in  the  last  Talk.  Hot,  alkaline  waters  are 
supposed  to  have  had  principal  agency  in  the  work. 
But  where  the  native  metals  occur,  as  gold,  silver,  or 
copper,  we  must  suppose  that  a  dry  fusing  heat  has 
been  present  to  reduce  the  ores  previously  formed, 


The  King  of  Metals.  157 

or  drive  together  metallic  particles  disseminated 
through  the  rock  ;  or  we  must  suppose  that  an  elec- 
tro-chemical deposition  has  taken  place  from  a  met- 
alliferous solution,  as  in  the  electro-plating  process. 
In  some  way,  at  least,  particles  of  a  particular  kind 
become  aggregated  in  "veins,"  in  "lodes,"  in  "seg- 
regations" :  and  thus  the  huge  lenticular  masses  of 
haematite  may  have  been  formed. 

Perhaps  this  theory  is  sustained  by  the  relations  of 
iron  ores  to  the  stratification.  Often  all  stratification 
is  obscure  or  wanting  ;  often  the  stratification  of  the 
country  rock  can  be  traced  through  the  ore-body  ;  not 
unfrequently  the  ore-mass  is  a  vast  stratified  forma- 
tion. Pilot  Knob,  in  Missouri,  is  a  great  iron-schist 
— a  schistose  formation  in  which  the  once  dissem- 
inated iron  particles  appear  to  have  been  driven  by 
some  agency,  into  a  particular  part  of  the  formation. 
In  this  case,  the  richest  part  of  the  formation  is  at 
the  pinnacle  of  the  knob,  and  the  schist  decreases  in 
richness  as  we  descend  to  the  base. 

Now,  there  are  two  suggestions  in  reference  to  the  The  varl. 
way  in  which  iron  ore  particles  have  been  accumu-  ous  modes 
lated — first,  fossilization  of  ancient  iron-bogs ;  second, 
segregation.  If  the  great  masses  found  in  metamor- 
phic  strata  seem  rather  to  be  the  results  of  segrega- 
tion, some  of  the  younger  iron  deposits  appear  to  be 
of  the  nature  of  fossilized  swamps.  Probably,  too, 
some  rich  stratified  ores,  like  those  back  of  Milwau- 
kee, and  those  near  Rochester,  New  York,  were  pre- 
cipitated in  shallow  seas— the  iron  brought  in  by 
springs.  This  is  a  third  suggestion. 

There  is  still  another  way  in  which  iron  combina- 
tions appear  to  accumulate.  It  is  a  modification  of 


158      Walks  and  Talks  in  the  Geological  Field. 

the  segregation  process.  You  have  seen,  sometimes, 
in  a  yellowish  or  reddish  sandstone — that  is,  a  fer- 
ruginous sandstone — some  concentric  bands  of  a 
deeper  color— bands  formed  by  an  increased  amount 
of  oxide  of  iron.  Now  observe  that  the  lines  of  strat- 
ification of  the  rock  pass  quite  through  these  sphe- 
roidal forms.  It  is  manifest,  therefore,  that  the 
spheroidal  aggregations  took  place  after  the  sedi- 
ments were  laid  down — after  the  rock  was  formed. 
Concre-  If  so,  then  the  iron  material  must  have  moved 
tionary  through  the  consolidated  rock.  How  did  it  move  ? 

iron. 

Could  solid  particles  of  iron-oxide  travel  from  all 
directions  toward  a  common  center,  and  all  halt  at  a 
common  distance  from  that  center  ?  Evidently  not, 
only  pure  water  or  clear  solutions  could  thus  move. 
We  may,  therefore,  conclude  that  the  iron  was  trans- 
ported and  accumulated  in  spheroidal  or  concretion- 
ary forms  in  a  state  of  solution  in  water.  It  must, 
therefore,  have  existed  as  a  protoxide,  and  must  have 
combined  with  further  oxygen  or  with  carbonic  acid 
subsequently.  When  combined  with  the  latter,  it 
forms  iron  carbonate,  and  this  is  one  of  the  ores  of 
iron.  As  an  ore  it  is  siderite.  It  possesses  various  de- 
grees of  purity.  Often  it  occurs  as  a  concretion  five 
to  eight  inches  long,  formed  in  the  rock  as  I  have 
just  explained.  It  may  thus  embrace  much  sand  or 
clayey  matter,  and  this  is  the  condition  in  which  the 
siderite  nodules  or  "clay  iron  stones"  are  found  in 
the  coal  measures  and  other  formations, 
ironoc-  go  you  perceive  that  iron  ores  do  not  occur  in 

curs  in 

masses  or  proper  veins.  They  are  isolated  masses,  or  they  are 
i'n'true110*  strata-  Tney  are  not  mined  out  through  shafts  and 
veins.  drifts  and  chambers,  like  the  ores  of  gold  and  silver, 


The  Crystals  of  the  Sea.  159 

but  mostly  in  open  excavations.  In  Salisbury,  Con- 
necticut, the  excavations  extend  into  cavernous,  de- 
ranged stratified  rocks,  and  many  of  the  cavities  are 
lined  with  a  black,  polished  coating  of  ore  which 
when  scratched  is  yellow,  and  therefore  limouite. 
This  limonite  has  been  in  solution.  It  has  filtered 
through  the  interstices  of  the  formation.  In  many 
of  the  cavities  are  beautiful  stalactitic  forms  hanging 
from  the  roof,  or  stretching  from  roof  to  floor.  These 
are  much  sought  as  fine  specimens  for  the  cabinet. 

The  mean   specific  gravity  of  the  whole  earth  is  w.    j 
twice  that  of  the  heaviest  rocks.     Is  that  due  to  com-  the  earth's 
pression  of  the  interior,  or  to  the  presence  of  some  j 
substance  heavier  than  the  ordinary  materials  at  the 
surface  ?    Some  have  suggested  the  probability  that 
the  earth's  central  mass  is  a  vast  ocean  of  molten 
iron.    It  will  be  remembered,  also,  that  iron  is  a 
chief  constituent  in  meteoric  masses. 


XXIII.     THE  CRYSTALS  OF  THE  SEA. 

SALT   AND  GYPSUM. 

LOOK  over  a  map  of  the  Caspian  Sea  and  notice  on 
the  eastern  side  a  roundish  bay  nearly  cut  off  from  Gulf, 
the  main  body.  This  is  the  Karab6ghaz  or  Black 
Gulf.  Though  appearing  so  small,  this  bay  is  about 
ninety  miles  across.  The  channel  which  connects  it 
with  the  Caspian  is  only  one  hundred  and  fifty  yards 
broad  and  five  feet  in  depth.  The  water  is  shallow, 
though  that  in  the  central  part  of  the  Caspian  at- 
tains a  depth  of  twenty-four  hundred  feet.  Through 
the  strait  connecting  the  Karab6ghaz  with  the  sea, 


160      Walks  and  Talks  in  the  Geological  Field. 

a  current  of  water  sets  out  from  the  Caspian  at  the 
rate  of  three  miles  an  hour.  The  inhabitants  of  the 
region  fancy  that  an  underground  passage  exists  from 
the  Karab6ghaz  to  the  Persian  Gulf  or  the  Aral  Sea. 
This,  however,  is  impossible,  since  the  Caspian  is 
eighty-four  feet  lower  than  the  ocean,  and  one  hun- 
dred and  seventeen  (some  assert  250)  feet  lower  than 
the  Aral.  The  vast  volume  of  water  discharged  into 
the  Karab6ghaz  is  lost  by  evaporation  from  its  sur- 
face. No  large  rivers  empty  into  it,  while  the 
climate  is  dry,  and  the  summer  intensely  hot. 
A  natural  The  water  of  the  Caspian,  as  you  know,  is  salt.  It 
salt  vat.  has  been  calculated  that  three  hundred  and  fifty 
thousand  tons  of  salt  are  carried  by  the  current  into 
the  Karab6ghaz  daily.  The  process  of  evaporation 
must  consequently  increase  the  saltness  of  the  water 
in  the  bay  ;  and  the  great  drain  from  the  sea  must 
tend  to  diminish  its  saltness.  Now,  as  a  fact,  the 
Caspian  possesses  only  about  half  the  saltness  of  the 
open  ocean,  while  the  Karab6ghaz  has  become  so  in- 
tensely salt  that  the  animals  which  once  inhabited  its 
waters  have  disappeared.  In  fact,  the  concentration 
has  gone  so  far  that  layers  of  salt  are  being  deposited 
on  the  mud  at  the  bottom.  In  all  probability  these 
processes  will  continue  in  the  future,  and  it  must 
be  anticipated  that  the  salt  deposit  will  increase  in 
thickness  as  long  as  this  gulf  exists.  Should  there 
be  an  elevation  of  the  strait  connecting  the  gulf  with 
the  sea,  the  gulf  would  speedily  dry  up,  and  all  the 
salt  contained  in  its  water  would  be  precipitated 
in  a  vast  bed  of  rock-salt.  Then,  should  a  depression 
of  the  isthmus  connecting  this  low  salt  formation 
with  the  sea  take  place,  there  would  be  a  new  influx 


The  Crystals  of  the  Sea.  161 

of  the  sea.  The  sediments  of  its  waters  would  be  de- 
posited upon  the  bed  of  rock-salt ;  and  new  precipita- 
tions of  salt  would  occur.  The  site  of  the  Kara- 
b6ghaz  would  then  be  a  great  salt-bearing  formation, 
like  those  formed  in  ancient  times  in  various  ages 
of  the  world. 

On  other  portions  of  the  Caspain  shores,  the  pro-  other  con- 
cess  has  been  brought  nearly  or  quite  to  completion.  centrating 
On  the  peninsula  Apsheron,  on  the  west  side  nearly 
opposite  the  Karab6ghaz,  are  ten  salt  lakes,  in  one  of 
which,  evaporation  has  gone  so  far  that  ten  thousand 
tons  of  salt  are  annually  removed  from  it.  Again,  in 
the  neighborhood  of  Novo  Petrovsk,  the  deep  inden- 
tation on  the  east  shore  was  once  a  large  bay,  which  is 
now  divided  into  a  number  of  basins  presenting 
every  degree  of  saline  concentration.  One  of  these 
still,  occasionally  receives  water  from  the  sea,  and  has 
deposited  on  its  banks  only  a  thin-  layer  of  salt.  A 
second,  still  full  of  water,  has  its  bottom  covered  ^by  a 
thick  crust  of  rose-colored  crystals  like  a  pavement  of 
marble.  A  third  exhibits  a  compact  mass  of  salt 
on  which  are  pools  of  water,  whose  surface  is  more 
than  a  yard  below  the  level  of  the  sea.  A  fourth  has 
lost  all  its  water  by  evaporation,  the  stratum  of  salt 
left  behind  being  uncovered  by  sand.  A  similar  con- 
centration is  taking  place  in  the  Karasu,  or  long  inlet 
setting  southward  from  the  northeastern  extremity 
of  the  Caspian. 

The  whole  Caspian  is  greatly  dwarfed  from  its  an- 
cient dimensions  by  the  process  of  evaporation,  and  it 
would  be  naturally  expected  that  the  salinity  of  the 
water  would  be  intensified,  as  in  the  Dead  Sea,  instead 
of  diminished.  The  intensification  has  really  taken 


162      Walks  and  Talks  in  the  Geological  Field. 


place,  but  under  such  circumstances  that  only  margi- 
nal portions  have  increased  in   saltness,  while  the 
main  body  has  been  weakened  by  the  influx  of  the 
great  rivers  Volga,  Ural,  Kuma  and  Terek. 
Similar         This  account  of  changes  taking  place  on  the  bor- 
conditions  ders  of  the  Caspian  wen  illustrates,  as  I  have  long 
once  pre- 

vailed in  believed,  the  method  of  accumulation  of  the  great 
our  salt  saj£  formations  of  geological  times.  In  western  New 
York,  in  certain  regions  great  beds  of  rock  salt  may 
be  reached  by  boring  to  a  certain  depth.  They  lie 
underneath  solid  sheets  of  limestone  and  thick  beds 
of  shale.  In  the  vicinity  of  Goderich,  Ontario,  and 
also  in  Michigan  at  sundry  localities—  Marine  City, 
St.  Clair,  Alpena  on  the  east  shore,  and  Manistee, 
Muskegon  and  Ludington  on  the  west  shore  —  vast 
deposits  of  rock  salt  are  found,  at  depths  from  a 
thousand  to  two  thousand  feet.  The  best  of  evidence 
exists  that  the  salt  bed  is  the  same  on  opposite  sides 
of  the  state,  and  extends  continuously  under  the 
state.  This  is  also  the  formation  which  supplies 
brine  for  the  works  at  Syracuse. 

Another  salt  formation  occurs  in  Michigan,  occupy- 
ing a  higher  geological  position  than  that  just  men- 
tioned. The  first  is  the  Salina  formation  in  the 
Upper  Silurian  (see  Table,  p.  85)  ;  this  is  the  Mich- 
igan Salt  Group,  in  the  Lower  Carboniferous.  From 
the  last,  the  wonderful  supplies  of  the  Saginaw 
valley  are  mostly  obtained.  From  the  Salina  form- 
ation the  supplies  eclipse  even  those  of  the  upper 
group.  At  Marine  City,  on  the  St.  Clair  River,  a 
delightful  steamboat  ride  from  Detroit,  are  works 
of  astonishing  magnitude  and  productiveness.  The 
great  salt  industry  of  Cheshire,  England,  is  sup- 


The  Crystals  of  the  Sea.  163 

ported  by  beds  of  rock  salt  sixty  to  a  hundred  feet 
thick,  and  underlying  strata  of  clay  and  gypsum,  and 
having  indurated  clays  and  gypseous  beds  under- 
neath. Much  of  the  salt  is  mixed  with  earthy  ma- 
terials, and  hence  is  redissolved  in  sea-water,  settled 
and  re-evaporated.  Other  salt  deposits  of  world-wide 
celebrity  occur  in  Poland,  Austria,  and  Germany. 
The  boring  at  Stassfurt,  Germany,  penetrated  1,066 
feet  of  rock  salt,  and  that  at  Sperenberg,  5,084  feet 
without  reaching  the  bottom. 

It  appears,  therefore,  that  the  evaporation  of  sea-  -yy^y 
water  has  taken  place  on  a  large  scale,  in  various  ages  brines  in 
of  the  world.    In  many  localities  the  salt  has  been  aSTrock 
again  dissolved  by  fresh  water  from  the  surface,  and  salt  in 
porous  formations  underlying  have  become  saturated  Ml 
with  brine.    This  is  the  case  with  the  Michigan  Salt 
Group  and  the  Onondaga  salines  of  New  York,  as 
also  those  on  the  Kanawha  and  Ohio  Rivers.      In 
some  cases  the  home  rocks  possess  sufficient  porosity 
to  retain  the  brine.    In  other  localities  the  solid  salt 
exists,  but  it  is  so  mixed  with  clay  as  to  require  re- 
dissolving  and  purification.    This  as  I  said,  is  the 
case  in  Cheshire.      In  some  countries,  as  in  Poland 
and  Austria,  great  mines  are  excavated  in  immense 
salt  formations.     In  Michigan  the  rock  salt  possesses 
great  purity,  but  it  lies  so  deep  that  the  expense  of 
sinking  and  maintaining  shafts  has  so  far,  led  to  the 
expedient  of  dissolving  the  salt  in  its  place,  and  then 
pumping  out  the  saturated  brine.    At  Marine  City, 
water  pumped  from  the  St.  Glair  River  is  forced  down 
the  bore-hole,  where  it  dissolves  the  salt,  and  is  then 
forced   out  by  the  same  process  into  great   tanks, 
where  the  brine  settles,  and  then  in  other   tanks 


164     Walks  and  Talks  in  the  Geological  Field. 

undergoes  evaporation  by  means  of  heat  from  steam 
pipes  immersed  in  the  brine.  The  precipitated  salt 
is  raked  out  by  automatic  rakes,  allowed  to  drain, 
then  dried  and  barreled.  At  Syracuse  and  in  the 
Saginaw  valley,  the  brine  is  pumped  from  the  wells 
and  settled  and  evaporated.  Formerly  much  evapo- 
ration was  done  in  kettles  over  a  fire.  More  recently, 
pans  and  steam  have  been  employed.  A  large 
amount  of  salt  is  produced,  especially  at  Syracuse,  by 
spontaneous  evaporation  in  shallow  vats  exposed  to 
the  sun  and  air,  and  covered  in  rainy  weather,  by 
light  roofs  moved  on  rollers. 
Order  of  The  natural  brines  of  Saginaw  and  other  regions 

precipita-  contain  impurities.     In  the  process  of  evaporation 

tion  from 

brines.       those  least  soluble  are  first  precipitated  out,  and  then 

the  other  substances  in  the  inverse  order  of  their 
solubility.  Thus  the  brine,  which  is  limpid  and 
sparkling  on  its  escape  from  the  earth,  after  exposure 
to  the  air  forms,  by  peroxidation  of  the  iron  (see 
Talk  XXII)  a  red  deposit  which  is  insoluble,  and 
falls  to  the  bottom  of  the  settling  vat  —  generally 
hastened  by  some  coagulable  substance.  When  trans- 
ferred to  the  kettles  and  heated,  gypsum  is  the  first 
deposit,  and  this  adheres  firmly  to  the  surface.  Next, 
common  salt  crystallizes  out,  which  forms  on  the 
bottom  and  is  raked  from  the  kettle,  drained  and 
placed  in  bins.  The  water  remaining  is  called  "  bit- 
terns," in  consequence  of  other  bitter  and  nauseous 
substances  still  remaining.  Should  the  evaporation 
be  further  continued,  Epsom  salts  (magnesium  sul- 
phate) would  be  thrown  down  in  needle-shaped  crys- 
tals. Finally,  the  chlorides  of  calcium  and  potas- 
sium possess  such  affinity  for  water,  that  they  could 


The  Crystals  of  the  Sea.  165 

only  be  separated  completely  by  bringing  the  residue 
to  a  red  heat. 

This  order  of  precipitation  possesses  much  geolog-  The  same 
ical  interest.  In  some  salt  formations,  as  that  of  the  order  in 
Salina  group,  the  same  order  of  succession  has  been 
noted.  At  the  bottom  we  find  red  ferruginous 
clays.  Above  are  gypseous  clays  and  often  beds  of 
pure  gypsum.  Next  occurs  brine  or  salt.  Above  all 
are  found  limestones  still  retaining  the  needle- 
shaped  cavities  from  which  the  crystals  of  Epsom 
salt  have  been  dissolved,  or  in  which  crystals 
of  some  other  substance  have  been  deposited  as 
pseudomorphs — minerals  having  the  crystalline  forms 
which  characterize  other  minerals.  This  suc- 
cession observed  in  nature  is  a  confirmation  of  the 
theory  of  origin  of  salt  formations  by  evaporation 
of  gulfs  and  bays.  It  is  evident,  however,  that  such 
order  of  deposit  can  not  generally  be  observed  as  one 
single  circuit ;  because  irregular  irruptions  of  sea- 
water,  alternating  with  floods  from  land  and  periods 
of  dry  weather,  must  break  up  any  continuous  suc- 
cession from  beginning  to  end  of  the  history  of  a  salt 
basin,  and  must  lead  to  many  repetitions  of  strata  of 
the  various  kinds.  This,  however,  is  the  fact  uni- 
versally observed,  that  all  salt  formations  are  charac- 
terized by  the  presence  of  all  or  nearly  all  the  sub- 
stances found  existing  in  sea-water.  Gypsum,  es- 
pecially, is  always  associated  with  brine  and  salt ; 
and  that  is  the  reason  the  two  have  to  be  discussed 
together.  Other  substances,  found  equally  in  sea- 
water  and  natural  brines,  are  magnesia,  potash, 
bromine,  and  iodine. 


166      Walks  and  Talks  in  the  Geological  'Field. 


XXIV.     LIQUID  SUNLIGHT. 

PETROLEUM. 

The  search     THE  history  of  the  search  for  native  oil  is  romantic. 

for  oil.  Known  for  ages,  it  remained  a  mere  curiosity  till 
1859.  Even  in  America,  where  popular  intelligence 
is  supposed  to  utilize  every  possible  advantage,  pe- 
troleum rose  only  to  the  importance  of  a  quack  rem- 
edy for  aches  and  other  evils.  But  suddenly  it  as- 
sumed the  scepter  of  king.  Men  pursued  it  with  the 
sound  and  fury  of  dogs  on  the  track  of  their  prey. 
They  lost  their  power  of  reasoning  on  the  subject. 
They  could  not  be  convinced  that  mineral  oil  is  a 
geological  product,  fixed  in  its  relations  to  the  earth 
and  to  the  strata,  as  unchangeably  and  as  intelligibly 
as  iron  or  salt.  They  would  not  listen  to  the  counsel 
of  science.  Every  man  was  confident  in  his  self-wis- 
dom, and  never  inquired  on  what  grounds  he  be- 
lieved and  acted  as  he  did.  There  was  oil — millions 
of  barrels  of  it ;  and  many  investors  were  fortunate  if 
not  wise;  and  many,  though  wise,  were  not  fortunate. 
It  was  a  new  situation.  It  must  be  confessed  that 
geology  took  up  the  subject  as  a  novice  ;  though  with 
the  great  advantage  of  a  knowledge  of  certain  geo- 
logical principles  to  which  the  generation  and  accu- 
mulation of  petroleum  must  necessarily  conform. 

Principles      ^ow,  some  of  the  scientific  principles  which  must 

true  re-      hold  true  without  any  regard  to  the  particular  causes 

gardingoil 

and  its  oc-  an(l  conditions  of  oil-accumulation,  are  such  as  these  : 

currence.       ]    Oil  is  not  a  direct  deposit  from  the  sea  ;  it  is  the 


Liquid  Sunlight.  167 


product  of  some  changes  in  substances  which  formed 
part  of  the  ocean's  sediments. 

2.  Being  composed  of  carbon,  hydrogen,  and  oxy- 
gen, it  must  have  originated  from  organic  substances, 
either  vegetable  or  animal. 

3.  Being  lighter  than  water,  it  must  tend  to  rise 
through  the  water  which  saturates  all  rocks,  instead 
of  sinking.     The  source  of  the  oil,  therefore,  could 
never  be  in  any  formation  situated  at  a  higher  level 
than  the  place  of  the  oil.    This  is  a  principle  which 
the  crazy  crowd  could  never  be  taught.    The  oil,  for 
them,  was  always  a  "  drip  "  from  the  Coal  Measures. 

4.  A  good  "  surface  show  "  is  not  favorable,  since  it 
is  only  caused  by  the  escape  and  waste  of  the  oil ; 
while  the  thing  wanted  is  an  accumulation  or  re- 
tention of  the  oil— that  is,  an  absence  of  surface  show. 
This  the  contemners  of  scientific  guidance  could  not 
understand. 

5.  There  must  consequently  be  an  overlying  stra- 
tum which  is  impervious  to  oil,  to  prevent  the  prod- 
uct from  rising  to  the  surface,  to  be  wasted  in  a  "  sur- 
face show."    If  a  fissure,  even,  passes  through  this, 
the  oil  will  escape.    A  bed  of  clay  or  compact  shale 
might  serve  as  such  a  cover.     Compact  limestone 
might  serve  ;  but  most  limestones  are  too  much  shat- 
tered.   Indeed,  shattered  limestones,  in  some  cases, 
serve  as  reservoirs  for  the  accumulation. 

6.  The  accumulation   of  oil  must  be  determined, 
among  other  things,  by  the  attitudes  of  the  strata. 
The  trends  of  "oil  territory"  must  conform  to  the 
trends  of  formations.    The  situations  of  creeks  at  the 
surface  could  have  no  bearing  on  the  underground 
distribution    of  petroleum.      The  junction   of  two 


168      Walks  and  Talks  in  the  Geological  Meld. 

streams  and  the  location  of  a  sand-flat  could  sustain 
no  relation  to  strata  three  or  four  hundred  feet  be- 
neath. Whether  the  situation  were  in  a  ravine  or  on 
the  upland  could  make  no  difference  except  in  the 
depth  of  the  boring.  The  notion  of  "ranges"  and 
"  lines  "  in  the  distribution  of  productive  territory 
was  illusory  ;  since  this  is  determined  by  the  direc- 
tion, the  length,  and  the  breadth  of  the  formations 
which  furnish  the  requisite  conditions. 

7.  Petroleum  is  not  confined  to  any  particular  for- 
mation. For  many  years  it  has  been  knowrn  in  lim- 
ited quantities,  from  the  Eozoic  gneisses  to  the  Ter- 
tiary. The  assumption  was  misleading,  therefore, 
that  every  oil  region  must  be  supplied  under  the 
same  stratigraphical  and  topographical  conditions  as 
Venango  County,  Pennsylvania.  It  was  a  matter  of 
scientific  certainty  that  another  region  might  be  fed 
from  strata  of  a  different  geological  age,  of  a  differ- 
ent lithological  constitution,  dipping  in  a  different 
direction,  trending  to  other  points  of  the  compass, 
and  overlaid  by  different  topographical  features  at 
the  surface. 

All  these  principles,  I  have  said,  were  known  to 
science,  and  secured  to  the  scientific  man  certain  im- 
portant advantages  in  arriving  at  judgments  con- 
cerning prospects  of  success  in  a  proposed  enterprise. 
All  of  these  principles  were  disregarded  by  a  major- 
ity of  the  "oil  prospectors."  Some  men  under  pay 
from  capitalists  even  resorted  to  the  witch-hazel  fork 
in  quest  of  knowledge  on  which  capital  might  ven- 
ture investment. 

Let  me  now  add  some  principles  which  experience 
and  observation  have  pretty  well  established,  and 


Liquid  Sunlight. 


you  will  have  the  whole  philosophy  of  oil-finding 
and  oil-production.  It  is  generally  admitted  that  the 
porous  stratum  in  which  oil  accumulates  must  have 
an  arched  or  anticlinal  form.  Otherwise,  the  oil  will 
spread  laterally  to  an  indefinite  distance,  and  no  lo- 
cal accumulation  will  take  place.  On  the  contrary, 
the  oil  will  somewhere  find  an  outlet  to  the  surface. 

Another  doctrine  generally  accepted  is  the  vegetable 
origin  of  the  great  supplies  possessing  commercial 
importance.  It  is  admitted  that  animal  remains 
may  be  a  source  of  petroleum  to  a  small  amount. 

Again,  it  has  been  observed  that  every  great  oil-  The 
containing  reservoir  has  below  it — not  always  im-  source 
mediately  below— a  formation  of  the  nature  known 
as  black  bituminous  shale.    This  is  soft,  easily  cut 
with  a  knife,  and  contains  a  large  amount  of  vege- 
table matter.     Such  shales  are  generally  thought  to 
contain  quantities  of  remains  of  sea-weeds.     If  so, 
they  exist  in  a  comminuted  and  obscure  state. 

Probably  a  majority  of  geologists  entertain  the 
opinion  that  petroleum  is  produced  from  these  black 
shales  by  a  slow  spontaneous  distillation,  through 
the  action  of  the  heat  in  the  rocks.  By  artificial  dis- 
tillation, oil  is  readily  obtained  from  them,  and  little 
doubt  is  entertained  that  at  a  comparatively  low  tem- 
perature a  slow  natural  distillation  proceeds. 

Observation  has  shown  that  while  black  shales 
manifest  a  predisposition  to  the  production  of  oil, 
pure  vegetable  deposits  are  more  fixed.  Thus,  from 
proper  coal-beds  no  oil  proceeds ;  but  from  cannel 
coal  and  coaly  shales  oil  is  spontaneously  evolved,  as 
it  also  is  from  the  black  shales  where  the  vegeta- 
ble matter  has  not  attained  a  coaly  condition.  The 


170      Walks  and  Talks  in  the  Geological  Field. 

mixture   of  argillaceous  matter  with  the  vegetable 
material  seems  to  favor  the  oil-making  process. 
Gas  and         Natural  gas  has  an  origin  very  similar  to  that  of 
°1L  petroleum.    The  inflammable  gas  now  so  extensively 

employed  as  a  substitute  for  coal,  is  also  composed, 
like  petroleum,  of  carbon  and  hydrogen,  but  with 
a  larger  proportion  of  hydrogen.  It  must  be  derived, 
in  a  similar  way,  from  a  similar  source.  Petroleum, 
in  fact,  is  generally  associated  with  gas.  It  seems  to 
be  composed  of  the  heavier  and  more  fixed  com- 
pounds of  carbon  and  hydrogen — containing  much 
carbon,  while  gas  is  a  lighter  compound  with  more 
hydrogen.  Petroleum,  however,  is  not  a  simple  com- 
pound of  definite  composition,  but  a  mixture,  ap- 
parently of  many  compounds— the  more  fixed,  like 
asphalt  and  parafflne,  being  dissolved  in  the  fluids 
kerosene,  naphtha,  and  others.  It  is  evident  that 
natural  gas  may  wander  farther  away  than  oil  from 
the  formation  in  which  it  originates  ;  and  hence  there 
may  be  more  difficulty  in  tracing  it  to  its  real  source. 
It  may  become  widely  separated  from  apparent  con- 
nection with  oil.  It  may  also  be  distilled  from  shales 
not  possessing  the  requisite  richness  to  afford  oil. 
Hence,  in  some  regions,  as  Fremont,  Cleveland,  and 
other  localities  in  northern  Ohio,  it  issues  from  Cam- 
brian strata  which  furnish  no  indications  of  oil.  In 
western  Pennsylvania,  within  the  Coal  Measures,  the 
great  supplies  of  gas  are  yielded  probably,  by  the 
same  formations  as  supply  petroleum.  This,  how- 
ever, is  a  question  still  under  investigation. 
QJJ  Now  let  us  look  into  the  relations  of  things  in  some 

districts:    of  the  principal  oil-producing  regions.      The    most 
famous  is  that  of  northwestern  Pennsylvania.     The 


Liquid  Sunlight.  171 


surface  rocks  are  Coal  Measures  or  Lower  Carbon-  pennsyi- 
iferous  Sandstones  (Waverly  or  Catskill  sandstones)  vania, 
or  Chemung  sandstones — according  to  the  locality. 
The  oil  is  found  accumulated  in  the  sandstones ;  but 
its  source  is  believed  to  be  the  Genesee  Black  Shale, 
near  the  top  of  the  Hamilton  Group  (See  Table,  page 
85).     There  are  in  all  productive  situations,  shaly 
strata  also,  above  the  sandstone  reservoir,  which  pre- 
vent the  oil  from  escaping  to  the  surface.    The  situa-  Eastern 
tions  are  similar  in  eastern  Ohio  and  southern  New  New 
York.  York« 

In  Ontario  are  two  kinds  of  oil,  and  two  different  Ontarl0) 
reservoirs.  The  thick  lubricating  oil  accumulates  in 
a  gravel  bed  at  the  bottom  of  the  Drift,  and  is  con- 
fined by  the  clay  sheets  of  the  overlying  Drift.  Its 
source  is  probably  the  Genesee  Shale,  which  im- 
mediately underlies,  but  thins  out  a  half  mile  further 
east.  The  more  abundant  petroleum  is  found  stored 
in  fissures  and  cavities  of  the  Hamilton  limestone ; 
and  its  source  is  probably  the  black  Marcellus  shale 
next  below  the  limestone.  These  cavities  often  con- 
tain water  under  the  oil,  and  gas  above.  If  the  auger 
enters  the  upper  part,  gas  escapes  at  first,  but  when 
this  is  exhausted,  oil  may  be  pumped.  When  the 
oil  is  exhausted,  water  follows.  If  the  auger  enter 
below  the  surface  of  the  oil,  the  reaction  of  the  gas 
forces  the  oil  to  the  surface,  and  a  "flowing  well" 
exists.  When  the  oil  becomes  lowered  to  the  place 
of  the  perforation,  gas  escapes  till  the  pressure  is  re- 
lieved. Then,  if  any  oil  remains,  it  may  be  pumped. 
Lastly,  the  water  may  be  pumped.  If  the  auger  en- 
ters the  cavity  below  the  surface  of  the  water,  the 
reaction  of  the  gas  forces  first  water  to  the  mouth 


172      Walks  and  Talks  in  the  Geological  Field. 

of  the  well ;  then  when  the  bottom  of  the  oil  is 
lowered  to  the  orifice,  oil  is  forced  out  till  its  surface 
subsides  to  the  orifice,  when  finally  the  gas  escapes. 
No  oil  now  remains  in  the  cavity. 

California,  In  California  an  oil-producing  shale  extends 
through  the  Eocene  (Tertiary)  of  the  Coast  Ranges ; 
but  south  of  San  Francisco  these  strata  mostly  stand 
on  edge,  and  most  of  the  fluid  oil  has  escaped,  leav- 
ing large  quantities  of  tarry  asphaltum,  which  har- 
dens on  exposure  to  the  air.  North  of  San  Francisco, 
however,  these  shales  are  horizontal,  and  oil  has 
accumulated  in  considerable  quantities.  But  the 
chief  supply  of  petroleum  in  California  is  found  in 
the  less  disturbed  regions  south  of  San  Francisco, 
chiefly  in  Los  Angeles  and  Ventura  counties.  The 
total  product  of  the  state  in  1884  was  262,000  barrels. 
Russian  I11  foreign  countries,  the  most  productive  territory 
oil  district.  js  the  Baku  region  in  Russia,  near  where  the  Caucasus 
abuts  against  the  Caspian.  Here  is  an  area  of  14,000 
square  miles  which  is  producing,  under  treatment 
assimilated  to  that  employed  in  America,  quantities 
which  promise  to  interfere  seriously  with  the  export 
of  American  oil.  Six  hundred  wells  have  been  bored, 
and  one  spouting  well  is  represented  to  have  pro- 
duced 50,000  barrels  a  day.  The  most  copious  Penn- 
sylvania well  flowed  9,000  barrels  a  day,  and  the  most 
productive  Canadian  well,  7,500  barrels. 


Gaseous  Sunlight.  173 


XXV.     GASEOUS  SUNLIGHT. 

NATURAL  GAS— ITS  WONDERS  AND  ITS  GEOLOGY. 

ILLUMINATING  and  Heating  Gas  is  one  of  the  pro- 
ducts of  the  earth.  Its  escape  is  a  geological  phenom- 
enon. It  was  stated  in  the  last  talk  that  its  origin 
is  undoubtedly  similar  to  that  of  oil,  and  thatV)il  is 
chiefly  the  product  of  the  distillation  of  shales 
charged  with  vegetable  matter— probably  ancient  sea- 
weeds. As  sunlight  is  the  active  agent  in  vegetable 
growth,  a  stem  or  a  leaf  is  simply  a  body  of  trans- 
formed sunlight.  When  imbedded  in  the  rocks  it  is 
strictly  and  literally  fossil  sunlight.  In  petroleum, 
ancient  sunlight  is  preserved  in  liquid  form  ;  in  nat- 
ural gas  it  is  gaseous. 

The  escape  of  burning  gas  from  the  earth  has  been  Earlier 

observed  for  ages.     For  more  than  fifty  years,  the  gas  knowl- 

edge  of 
escaping  with  the  brine  from  the  wells  of  the  Kana-  natural 

wha  Valley,  West  Virginia,  has  been  employed  in  &as. 
the  evaporation  of  the  brine.  It  has  long  been  util- 
ized in  some  salt  mines  where  it  escapes  through 
crevices.  In  a  similar  way,  it  enters  coal  mines,  and 
is  known  to  miners  as  fire  damp,  since,  mixed  with 
a  certain  proportion  of  atmospheric  air,  it  becomes 
violently  explosive.  The  Chinese  have  for  centuries 
employed  natural  gas  for  lighting  and  heating.  On 
the  Cumberland,  in  Kentucky,  gas  accumulates  in 
underground  reservoirs,  and  the  elastic  pressure  is 
sometimes  attended  by  explosions,  constituting  earth- 
quakes of  local  extent,  and  lending  some  plausibility 


174     Walks  and  Talks  in  the  Geological  Field. 

to  the  ancient  theory  of  those  phenomena.  At  Fre- 
donia,  New  York,  are  gas  emissions  which  have 
attracted  attention  for  many  years,  and  have  long 
been  utilized  for  lighting  and  heating.  A  gas  spring 
was  discovered  here  in  1821.  The  gas  at  that  time  ac- 
cumulated was  used  for  lighting  a  mill  and  several 
stores.  It  was  also  introduced  into  a  few  public  build- 
ings, and  was  brought  to  the  attention  of  Lafayette 
when  he  passed  through  the  village  in  1824.  Sub- 
sequeutly,  a  shaft  was  sunk,  and  sufficient  gas  con- 
centrated to  supply  thirty  burners.  Thirty-seven 
years  afterward,  another  shaft  was  sunk  thirty  feet, 
and  two  borings  were  made — one  to  150  feet.  In 
1858,  two  thousand  cubic  feet  of  gas  were  delivered 
daily  through  the  village. 

Recent          During  the  years  of  the  great  oil  excitement,  from 
discov-       186Q  to  1870j  manv  Of  the  borings  for  oil  reached  only 

gas.      In  Knox  County,  Ohio,  in  1860,  two  wells  were 
Knox  Co., 

Ohio,  sunk  for  oil.  In  both,  streams  of  salt  water  were 
intercepted,  and,  at  about  six  hundred  feet,  an  im- 
mense reservoir  of  gas  was  struck.  The  gas  ejected 
the  water  with  great  violence.  The  first  well  was 
bored  in  the  winter,  and  the  water  soon  covered  the 
derrick  with  ice,  forming  a  kind  of  chimney  sixty 
feet  in  height.  Through  this,  the  water  was  thrown, 
at  intervals  of  about  one  minute,  to  double  that 
height,  or  120  feet.  After  the  water,  and  with  it, 
came  a  great  rush  of  gas,  which  continued  until  the 
pressure  below  was  relieved,  when  the  water  again 
began  to  accumulate,  and  was  again  ejected.  The 
process  was  entirely  analogous  to  the  action  of  the 
geysers  described  in  Talk  XIV.  In  the  Knox  County 
well,  gas  took  the  place  of  steam  in  the  geyser. 


Gaseous  Sunliqht.  175 


When  the  derrick  was  covered  with  ice,  the  gas 
escaping  from  the  well  was  frequently  ignited,  and 
the  effect,  especially  at  night,  of  this  fountain  of 
mingled  fire  and  water,  shooting  up  to  the  height 
of  one  hundred  and  twenty  feet,  through  a  great 
transparent  and  illuminated  chimney,  is  said  to  have 
been  indescribably  magnificent. 

When  I  visited  the  spot,  in  1866,  a  two-inch  gas 
pipe  had  been  fixed  in  the  orifice  of  the  second  well, 
and  the  gas  was  escaping  with  a  power  and  volume 
which  were  startling.  The  sound  could  be  heard  for 
a  quarter  of  a  mile.  The  pressure  was  two  hundred 
and  sixty-two  pounds  to  the  square  inch,  as  reported 
by  Mr.  Peter  Neff.  The  ignited  jet  formed  a  flame 
twenty  feet  in  length,  and  as  large  around  as  a  hogs- 
head. It  was  an  exciting  spectacle.  If  the  stop-cock 
were  closed  a  few  minutes  and  again  opened,  the 
accumulated  pressure  gave  a  volume  of  flame  as 
large  as  a  house.  The  supply  of  gas  here  was  suffi- 
cient to  illuminate  a  large  city.  Ten  years  after- 
ward, personal  information  from  Mr.  Neff,  under 
whose  direction  the  work  had  been  done,  assured 
me  that  these  wells  continued  to  "blow,"  and  he 
was  then  manufacturing  from  the  gas  a  refined  qual- 
ity of  lampblack. 

In  Michigan,  certain  parts  of  Wayne,  Oakland, 
and  Macomb  counties  appear  to  be  underlaid  by  con- 
siderable reservoirs  of  gas.  In  1875,  a  gas  well  was 
struck  three  miles  west  of  Royal  Oak,  at  the  depth  of 
a  hundred  feet.  In  1877,  a  well  eight  miles  southeast 
of  the  village,  at  the  depth  of  one  hundred  and  fifty 
feet,  reached  confined  gas  which  threw  the  tools 
into  the  air.  It  is  said  that  much  sand  escaped, 


176      Walks  and  Talks  in  the  Geological  Field. 

and  a  stone  weighing  "  several "  pounds  was  thrown 
over  a  barn  "  forty  rods  distant."  The  well  was  sub- 
sequently filled  —  evidently  after  the  high  pressure  of 
the  gas  had  subsided.  In  1879,  at  a  place  five  miles 
northeast  of  the  same  village,  a  well  bored  one  hun- 
dred feet  secured  a  supply  of  gas  which  has  since 
been  used  for  illuminating  purposes.  Three  miles 
south  of  the  village,  a  powerful  explosion  revealed 
the  uncovering  of  a  gas  reservoir  in  1880.  After 
burning  two  years,  two  other  gas  wells  were  bored, 
and  the.  united  illumination  rendered  newspaper 
print  legible  at  night,  at  the  distance  of  one  hun- 
dred yards.  In  1883,  a  gas  vein  was  reached  at 
ninety-eight  feet,  which  furnished  a  flame  twenty- 
feet  high.  In  1884,  on  deepening  this  well,  water 
was  found,  and  additional  gas  which  threw  the 
water  to  the  height  of  twenty  feet.  Many  other  oc- 
currences of  a  similar  nature  have  been  known  in 
this  part  of  Michigan. 

At  West  Bloomfield,  New  York,  a  well  bored  five 
hundred  feet  emitted  gas  with  great  force.  At  Erie, 
Pennsylvania,  Conneaut,  Painesville,  Cleveland,  and 
Fremont,  in  Ohio,  a  number  of  wells  have  been  suc- 
cessfully bored.  At  Buffalo,  New  York,  gas  with  a 
pressure  of  one  hundred  and  thirty-one  pounds  to 
the  square  inch  issued  from  a  well  six  hundred  and 
forty  feet  deep.  At  Cumberland,  Maryland,  a  gas 
well  burned  for  two  years.  Some  six  miles  east  of 
Crab  Orchard,  Kentucky,  is  a  burning  spring,  the 
water  in  which  is  in  a  constant  state  of  ebullition 
from  the  escape  of  gas.  "  Regularly  every  day," 
says  J.  F.  Henry,  "between  four  and  five  o'clock  in 
the  afternoon,  it  overflows  ;  a  large  quantity  of  gas  is 


Gaseous  tiunliqht.  177 


liberated,  and  if  a  torch  is  applied,  aflame  results." 
At  Fairview,  Pennsylvania,  a  well  drilled  for  oil,  in 
1870,  to  the  depth  of  one  thousand  three  hundred  and 
thirty-five  feet,  yielded  an  immense  volume  of  gas 
through  a  six-inch  pipe,  with  so  much  noise  as  to  be 
heard  for  a  distance  of  two  miles.  The  pressure  was 
eighty  pounds  to  the  square  inch.  The  gas  was  em- 
ployed in  establishments  in  Fairview,  Petrolia,  Karns 
City,  and  Argyle,  besides  furnishing  fuel  used  in 
drilling  some  forty  other  wells.  In  the  same  year, 
a  well  bored  near  Titusville  discharged  four  million 
cubic  feet  per  day.  At  East  Sandy,  in  the  same  oil 
district,  a  gas  well  struck  in  1869  resisted  all  efforts 
to  extinguish  its  burning.  "  It  roared  like  a  cata- 
ract and  could  be  heard  for  miles." 

Within  a  couple  of  years,  large  supplies  of  gas 
have  been  obtained  in  northern  Ohio,  by  boring 
down  to  the  Trenton  Limestone — at  least,  into  the 
Cambrian ;  for  some  doubt  exists  as  to  the  precise 
formation.  It  is  announced  (January  1886,)  that  Fre- 
mont, Ohio,  has  reached  a  supply  of  two  million  feet 
daily.  It  is  also  reported  that  gas  and  oil  have  been 
obtained  at  Lima,  Ohio,  at  the  depth  of  one  thousand 
two  hundred  and  fifty-one  feet.  The  gas  produces  a 
jet  of  flame  thirty  feet  high. 

The  vicinity  of  Pittsburg,  however,  surpasses  all  Natural 
other  regions  in  abundance  of  gas-supply.  The  sur- 
rounding  country  seems  to  be  underlaid  by  reser- 
voirs of  incredible  capacity.  These,  or  some  of  these, 
have  been  tapped,  and  the  product  has  come  into  ex- 
tensive use  in  furnace  and  other  operations.  Mr. 
William  Metcalf,  writing  in  November,  1884,  said : 
"An  observer  standing  on  a  hill-top  in  Allegheny 


178      Walks  and  Talks  in  the  Geological  Field. 

township,  Westmoreland  County — say  about  three 
miles  southeast  of  the  confluence  of  the  Allegheny 
and  Kiskiminetas  rivers — can  see,  on  a  dark  night, 
on  the  northwestern  horizon,  the  reflection  of  the 
lights  from  the  Butler  County  wells ;  to  the  north, 
the  lights  from  the  wells  in  the  direction  of  Kittan'- 
ning  ;  to  the  northeast,  the  Leachburg  and  Apollo 
wells  ;  to  the  southeast,  the  Murraysville  wells,  and 
to  the  southwest,  the  lights  of  the  Tarentum  wells. 
Off  in  Washington  County,  and  down  toward  Steu- 
benville,  there  are  other  wells,  while  at  Hulton,  in 
Pittsburg,  in  the  east  end  at  Soho,  at  Brownstown, 
at  Sligo,  and  in  Bayardstown,  there  are  wells  upon 
wells,  roarers  and  gushers.  Some  of  these  wells  give 
out  their  gas  at  an  enormous  pressure.  A  gauge  on  a 
six-inch  pipe  situated  some  miles  from  the  wells,  reg- 
istered one  hundred  and  twenty  pounds  to  the  square 
inch,  and  the  noise  of  the  rushing  gas  indicated  that 
the  gauge  was  about  right." 

The  Burns  Two  of  the  most  prolific  of  these  wells,  the  Burns 
and  the  Delamater>  have  been  described  by  the  late 
Professor  J.  Lawrence  Smith;  "  These  are  separated 
by  at  least  half  a  mile,  and  are  located  in  Butler 
County,  seven  miles  northeast  of  Butler,  and  about 
fifteen  miles  from  the  Harney  wells,  of  which  the 
gas  is  conducted  to  Pittsburg.  The  two  wells  are  lo- 
cated about  thirty  miles  in  a  straight  line  from  Pitts- 
burg. Their  depth  is  about  one  thousand  six  hun- 
dred feet,  down  to  the  fourth  sand  stratum  so  well 
known,  at  least  by  name,  to  those  engaged  in  the 
petroleum  production.  The  Burns,  it  is  believed,  has 
never  yielded  oil ;  but  the  Delamater  first  carried  to 
the  third  sand  layer  (the  oil  men  mean  sandstone 


Gaseous  Sunlight.  179 


when  they  say  '  sand  '),  was  a  petroleum  well  at  one 
thousand  six  hundred  feet.  Sunk  afterward  to  the 
fourth  stratum,  it  gave  gas  at  such  a  pressure  that 
the  tools,  of  one  thousand  seven  hundred  and  sixty 
pounds  weight,  could  be  withdrawn  by  hand.  Each 
well  is  five  and  five  eighths  inches  in  diameter." 

The  Delamater  is  the  more  remarkable.  It  furnishes 
light  and  fuel  to  all  the  vicinity,  including  the  vil- 
lage of  Saint  Joe.  It  is  situated  in  a  valley  sur- 
rounded by  high  mountains,  which  reflect  and  con- 
centrate the  light  of  the  ignited  gas.  Many  conduits 
start  from  the  well ;  one  leads  the  gas  directly  to  the 
cylinder  of  a  strong  motor,  which,  by  its  pressure, 
acquires  a  prodigious  velocity.  Another  pipe  feeds  a 
flame  capable  of  reducing  as  much  iron  ore  as  half 
the  furnaces  of  Pittsburg.  At  sixty-four  feet  dis- 
tant is  the  principal  escape  orifice  of  the  well.  From 
a  tube  three  inches  in  diameter,  a  column  of  fire 
forty  feet  high  shoots  forth  with  a  roar  that  fairly 
makes  the  hills  tremble.  During  a  calm  night  the 
noise  can  be  heard  at  a  distance  of  fifteen  miles.  At 
four  miles,  the  sound  resembles  that  of  a  railroad 
train  crossing  a  bridge  near  at  hand,  and  finally,  as 
the  escape  orifice  is  reached,  the  roar  is  like  that  of  a 
thousand  locomotives  blowing  off  steam  together. 
At  the  well,  in  a  tube  of  five  and  five  eighths  inches, 
the  pressure  is  about  one  hundred  pounds  per  square 
inch  ;  in  a  tube  of  two  inches,  in  which  the  gas  is  led 
to  Freeport,  fifteen  miles  distant,  the  pressure  is  one 
hundred  and  twenty-five  pounds.  The  ascending 
velocity  is  one  thousand  seven  hundred  feet  per  sec- 
ond, and  if  this  be  multiplied  by  the  area  of  the 
tube,  24.7  square  inches,  a  yield  of  two  hundred  and 


180     Walks  and  Talks  in  the  Geological  Field. 

eighty-nine  cubic  feet  per  second,  or  about  one  mil- 
lion cubic  feet  per  hour,  is  determined.  This  is  one 
thousand  four  hundred  and  eight  tons  of  gas  daily. 
This,  for  heating  purposes,  is  estimated  as  equivalent 
to  two  thousand  tons  of  bituminous  coal, 
import-  A  year  ago,  the  daily  consumption  of  natural  gas 

anceofgas  for  fuej  purposes  in  the  city  of  Pittsburg,  was  fifteen 
to  Pitts- 
burg,         to  twenty  million  cubic  feet.    The  Consolidated  Fuel 

Gas  and  Penn  Fuel  companies  were  delivering  from 
Murraysville,  through  four  lines  of  pipe,  ten  million 
cubic  feet  per  day.  Another  line  then  building  was 
intended  to  increase  the  flow  to  fifteen  or  seventeen 
million  cubic  feet.'  The  Washington  Gas  company 
had  a  pipe  line  twenty  miles  in  length  from  the  fa- 
mous McGingan  well  in  Washington  County.  To 
this  they  were  adding  an  eight-inch  line,  which 
would  increase  their  capacity  to  five  million  feet. 
The  Philadelphia  company  was  then  constructing 
three  gigantic  lines — one  from  Murraysville,  another 
from  Tarentum,  and  a  third  from  the  famous  West- 
inghouse  wells  at  Homewood,  within  the  city  limits. 
These  lines  would  have  a  combined  capacity  of  about 
thirty  million  feet  per  day.  The  Carpenter  company 
were  arranging  to  deliver  four  million,  and  the 
Chambers  company  three  million  cubic  feet.  Thus 
the  enormous  aggregate  of  sixty  million  feet  was  pro- 
vided for  ;  and  even  this  would  not  exhaust  the  sup- 
ply already  existing.  Sixty-five  to  seventy  million 
cubic  feet  were  daily  wasting— in  the  Murraysville 
district  alone. 

Wastage  ^ne  aggregate  wastage  as  indicated  by  data  still 
more  recent,  surpasses  all  which  would  be  suspected 
from  the  facts  given  above.  It  is  alleged  (March, 


Gaseous  Sunlight.  181 

1866),  that  in  the  entire  gas  field  about  Pittsburg, 
two  hundred  and  sixty-four  million  cubic  feet  of  gas 
are  daily  wasted.  One  thousand  cubic  feet  are  esti- 
mated to  equal  one  bushel  of  coal  in  heating  prop- 
erty. This  would  make  an  equivalent  of  two  hun- 
dred and  sixty -four  thousand  bushels  of  coal  burned 
in  the  air  each  day.  A  miner  can,  on  an  average,  dig 
seventy  bushels  of  coal  a  day.  The  waste  then, 
would  be,  in  round  numbers,  equal  to  the  daily  work 
of  thirty-eight  hundred  miners— or  about  the  whole 
number  employed  in  the  Pittsburg  district. 

This  gas  is  a  complex  mixture  of  hydrocarbons.    It  Compo_ 
differs  from  coal-gas,  as  also  from  gas  made  from  pe-  sition  of 
troleum.      Its   main   ingredient    is    "  Marsh   gas,"  g^sa^d 
which,  next  to  hydrogen,  is  the  lightest  substance  fuel  value, 
known,  consisting  of  seventy-five  per  cent  of  carbon 
and  twenty-five  per  cent  of  hydrogen,  and  having  a 
specific  gravity  of  0.5576,  that  of  air  being  unity. 
The  mixed  natural  gas  has  a  specific  gravity  ranging 
from  0.51  to  0.7.    That  supplied  to  Pittsburg  may  be 
averaged  at  0.6,  from  which  it  would  appear  that  the 
gas  for  which  provision-  was  making  in  1884,  was 
equivalent  to  about  forty-nine  hundred  tons  of  bitu- 
minous coal  in  heating  capacity. 

For  heating  purposes,  natural  gas  excels  coal  gas 
thirty-three  and  one  third  per  cent.  Used  in  the 
crude  way  twenty  cubic  feet  of  gas  equal  one  pound 
of  coal.  Used  in  the  ordinary  way,  11.29  cubic  feet 
equal  one  pound  of  coal.  Used  in  the  most  econom- 
ical way,  8.92  cubic  feet  equal  one  pound  of  coal.  For 
illuminating  purposes  it  possesses  only  half  the  value 
of  good  coal  gas  ;  although  it  has  been  asserted  of  the 
Fredonia  gas  that  it  equals  coal  gas  in  respect  to  in- 


182      Walks  and  Talks  in  the  Geological  Field. 

tensity  of  light,  and  is  consumed  but  half  as  fast. 
The  industrial  changes  effected  in  the  city  of  Pitts- 
burg  by  the  use  of  natural  gas,  are  of  a  revolution- 
ary character.  In  the  city  and  surrounding  country, 
not  less  than  ten  million  dollars  have  been  invested 
within  a  year,  said  a  writer  in  1884.  "  A  year  ago 
the  business  was  insignificant ;  to-day,  it  ranks  in 
importance  with  the  iron,  steel,  glass,  and  coal  inter- 
ests of  western  Pennsylvania.  There  are  at  present 
ten  iron  and  steel  mills  in  this  city  using  this  gas  in 
their  puddling  furnaces  and  under  their  boilers  ;  a 
dozen  more  are  busy  making  arrangements  for  its  in- 
troduction, and  almost  every  manufacturing  firm 
using  steam  is  awaiting  the  completion  of  the  neces- 
sary pipe  lines.  Six  glass  factories  in  the  city,  and 
seven  others  in  the  immediate  vicinity  are  using  it. 
Every  brewer  in  the  city  uses  it.  Two  of  the  largest 
hotels  use  it  exclusively  for  cooking  purposes.  For 
general  household  use,  on  account  of  its  cheapness, 
cleanliness,  and  convenience  of  application,  it  has 
no  rival." 

The  city  of  Buffalo  is  also  said  to  be  laying  pipe 
lines  for  gas  from  the  Pennsylvania  gas  districts. 

Thus,  strange  as  it  seems,  the   sea-weeds  which 
waved  their  graceful  fronds  in  the  oceans  of  millions 
of  years  ago,  are  smelting  the  iron  for  the  pipes  des- 
tined to  bring  their  transformed  constituents  to  the 
sites  of  gigantic  industries,  and  warming  the  dwell- 
ings of  the  populations  which  conduct  them. 
The  future      Will  these  marvelous  supplies  hold  out?    That  is 
of  natural  the    question    which    the   owners    of    the    millions 
p^SU)       invested   are   anxiously   asking.    Probably,    as   has 
been  proved  with  petroleum,   particular  wells   will 


Solidified  Sunlight.  183 

gradually  diminish  in  supply  ;  many  will  cease  to 
yield  ;  some  will  continue  indefinitely.  But  prob- 
ably, also,  as  in  the  case  of  petroleum,  new  supplies 
will  be  discovered,  and  even  increasing  demands  will 
be  met  for  many  years  in  the  future. 


XXVI.     SOLIDIFIED  SUNLIGHT.  • 

COAL  AND  COAL-BEDS. 

I  SIT  by  my  genial  grate,  this  pinching  winter  Coansa 
evening,  and  watch  the  play  of  the  flames  which  marvel, 
leap  from  the  coal  and  play  with  the  draughts  of  air 
passing  up  the  chimney.  Curious,  is  this  coal— this 
combustible  rock,  wonderful,  and  abounding  in  sug- 
gestions. This  warmth  is  yielded  by  combustion. 
This  rock  burns  up.  That  which  burns  up  is  essen- 
tially carbon,  or  a  hydrocarbon.  Carbon,  as  we  see  in 
charcoal,  burns  without  any  brilliant  flame,  and 
without  smoke.  Hydrocarbon,  as  we  see  in  kerosene 
and  illuminating  gas,  burns  with  a  bright  flame.  The 
coal  in  the  grate  emits  a  moderately  brilliant  flame. 
It  is  a  mass  of  carbon  saturated  with  some  liquid 
or  gaseous,  or  perhaps,  bituminous,  hydrocarbon. 
We  are  induced  to  trace  its  carbon  to  a  vegetable 
origin.  Now,  if  we  look  over  a  pile  of  coal  we  shall  vegetable 
probably  detect  some  indications  of  vegetable  tissue.  °rigin 
In  some  coals  of  the  soft  kind,  we  may  find  masses  of 
woody  fiber — black  and  brilliant,  like  some  charcoal. 
In  some  of  the  shale  attached  to  pieces  of  coal,  or 
mingled  with  the  coal,  are  some  impressions  like  fern 
fronds.  If  we  go  to  the  mines,  we  even  discover 
stems  of  moderate  sized  trees  imbedded  in  the  shales 


184      Walks  and  Talks  in  the  Geological  Field. 


above  the  coal,  and  occasionally  in  the  coal  itself. 
Again,  if  we  prepare  exceedingly  thin  slices  of  coal, 
and  remove  the  black  matter  by  proper  treatment, 
we  may  detect,  by  means  of  the  microscope,  minute 
structures,  such  as  belong  to  vegetation.  All  these 
circumstances  then,  conspire  to  convince  us  that  the 
coal  is  of  vegetable  origin,  and  much  of  it  from  tree- 
like vegetation.  With  other  observations,  we  detect, 
many  times,  innumerable  spores  scattered  through 
the  coal.  These  are  cells  produced  by  vegetation 
which  is  flowerless.  They  answer  for  the  fruit,  but  are 
not  fruit,  as  the  term  is  usually  employed.  The  coal 
vegetation,  therefore,  was  without  flowers  or  fruits. 
Much  of  it,  as  we  readily  discover,  was  of  the  nature 
of  ferns — some  of  them  tree-ferns,  such  as  grow  in 
our  times,  in  some  tropical  regions.  If  we  were  to 
search  further  we  should  find  traces  of  vegetation 
resembling  our  Horsetails  and  Ground  Pines.  So  we 
may  regard  ourselves  quite  justified  in  concluding 
that  the  coal  which  blazes  and  cheers  on  the  grate, 
was  once  in  the  condition  of  a  flowerless  tree,  rooted 
in  an  ancient  soil,  spreading  its  green  fronds  to  the 
sunlight,  decomposing  the  carbonic  acid  of  the  atmos- 
phere, fixing  the  carbon  in  its  own  tissues,  and  set- 
ting oxygen  free. 

So,  the  sun  was  shining  in  the  heavens  so  long  a 
sunlight,  time  ago.  The  plans  of  vegetable  structure  were  in  ex- 
istence, and  the  forces  of  vegetable  growth.  The  sun's 
emanations  of  light  and  heat  became  transformed 
into  stem  and  frond  and  tissue.  The  coal  is  ancient 
sunlight  that  has  been  locked  up  like  a  treasure  and 
buried  in  the  earth  for  ages.  Here,  in  this  flame,  the 
tissue-substance  goes  back  to  its  primeval  condition 


Solidified  Sunlight.  185 

— it  becomes  again  carbonic  acid,  and  mingles  again 
in  the  atmosphere  from  which  it  was  selected.  Here, 
in  this  flame,  the  old  warmth  reappears  ;  it  is  the 
warmth  of  the  sun  which  shone  in  the  Carboniferous 
Age.  Here,  in  this  flame,  the  old  sunlight  is  re- 
generated ;  this  is  the  very  sunlight  which  became 
latent  in  vegetable  cells  so  long  ago.  It  is  locked-up 
sunlight  set  free  after  a  long  imprisonment. 

There  are  several  varieties  of  coal ;  let  us  look  them  varieties 
over.  The  plumbago  of  your  pencil  is  essentially  of  coal- 
carbon.  We  can  take  common  coal  and  by  subjecting 
it  to  pressure  and  heat  while  excluded  from  the  air, 
convert  it  into  something  much  like  plumbago.  It 
often  occurs  in  iron-furnaces.  This  is  sometimes  Graphite, 
called  black  lead ;  but  it  contains  no  lead ;  its  more 
appropriate  name  is  graphite.  It  is  found  among  the 
metamorphic  rocks.  Whatever  it  was,  it  has  been 
pressed  and  baked  through  the  same  processes  which 
have  so  transformed  the  original  Eozoic  sediments. 
Since  graphite  can  be  prepared  from  coal,  we  may 
safely  assume  that  graphite  is  only  metamorphic 
coal.  Indeed,  there  are  regions  where  graphite 
occurs  in  the  same  formation  which  in  other  regions 
we  know  as  Coal  Measures.  But  the  strata  are  all 
metamorphic.  Most  graphite,  however,  belongs  to  a 
remoter  geological  age.  We  find  it  in  Vermont  and 
most  of  the  New  England  States  ;  also  in  northern 
New  York  and  many  other  American  and  foreign 
localities.  It  can  only  be  burned  at  a  high  temper- 
ature. 

Next  in  respect  to  hardness  and  difficulty  of  com-  Anthra. 
bustion  is  anthracite.   This  breaks  in  irregular  lumps,  cite, 
with  shining  surfaces,  and  burns  with  only  a  feeble 


186     Walks  and  Talks  in  the  Geological  Field. 

bluish  flame.  It  has  a  relatively  high  specific 
gravity,  and  furnishes  more  heat  per  ton  than  any 
other  species  of  coal.  Anthracite  is  found  in  situa- 
tions where  it  appears  to  have  been  subjected  to  a 
baking  and  hardening  process  which  has  driven  off 
most  of  the  volatile  hydrocarbons  found  in  other 
coals.  In  the  United  States,  southeastern  Pennsyl- 
vania is  the  chief  anthracite  region.  It  has  afforded 
an  enormous  quantity,  and  some  of  the  best  varieties 
are  said  to  be  about  worked  out. 

Bitumi-  The  other  varieties  of  coal  are  bituminous.  That  is, 
nous.  they  contain  hydrocarbons  partly  of  the  nature  of 
bitumen.  But  the  term  as  a  designation  for  a  variety 
is  restricted  to  the  black  coals  occurring  in  the  region 
east  of  the  Rocky  Mountains,  chiefly  in  the  Palaeo- 
zoic System.  In  structure  they  are  distinctly  strati- 
fied—sometimes with  films  of  earthy  matter  between 
the  laminse.  They  are  apt  to  break  in  flattish  or  thin 
fragments,  and  they  possess  an  earthy  or  resinous 
luster.  They  burn  with  much  bright  flame  which 
arises  from  the  hydrocarbons  expelled  and  ignited. 
These  coals  are  the  source  of  the  illuminating  gas  of 
our  cities. 

Cannei  From  the  typical  bituminous  coals  we  may  separate 
the  Cannei  Coals.  These  have  an  earthy  luster,  a  fine 
compact  constitution,  and  are  often  thick  bedded, 
with  only  obscure  stratification  within  the  bed.  They 
burn  freely  and  brightly  when  rich,  and  were  used  in 
the  earliest  manufacture  of  illuminating  gas  and 
kerosene,  or  "coal  oil."  This  manufacture  had  at- 
tained a  prosperous  stage  of  development  when  the 
discovery  of  the  large  supplies  of  petroleum  caused 
its  ruin.  Cannei  coal  has  no  standard  degree  of 


Solidified  Sunlight.  187 

purity.  It  consists  of  carbonaceous  and  aluminous 
particles  mixed  in  varying  proportions.  It  degener- 
ates, on  one  hand,  to  a  mere  black  shale,  and  on  the 
other,  attains  a  state  in  which  it  is  almost  free  from 
earthy  admixture. 

Among  the  typical  bituminous  coals,  we  distin-  caking 
guish  the  caking  and  the  non-caking.    The  former,  and .non- 
when  ignited,  seem  to  fry  with  an  exudation  of  a 
fluid  bitumen,  which  evolves  much  gas  and  hardens 
into  a  crust  somewhat  impervious  to  the  air,  and 
thus  obstructing  the  draft.    The  latter  burn  freely, 
without  an  incrustation. 

Besides  the  Palaeozoic  bituminous  coals  we  find  ex-  Bitumi- 
cellent  Mesozoic  bituminous  coals.     These  are  solid,  n«uscoal 
but  less  valuable  than  the  others ;  though  they  are  a  ZOiC  Age. 
boon  to  many  regions  otherwise  scantily  supplied 
with  fuel.    Of  this  kind  is  the  coal  mined  near  Eich- 
mond,  Virginia,  and  in  the  Deep  River  region  of 
North  Carolina  ;  also  the  excellent  coal  of  Wyoming 
and  that  of  similar  excellence  in  the  state  of  Wash- 
ington, in  the  Cascade  Mountains.    The  latter  ex- 
ists in  great  abundance  and  of  several  varieties,  one 
of  which  has  the  appearance  of  anthracite.    It  is 
widely  exported — to  San  Francisco  and  the  Hawaiian 
Islands. 

Brown  Coal  is  of  Csenozoic  age.     It  is  next  in  order  Brown 
of  hardness  and  value.    It  varies,  however,  from  a  coal, 
variety  quite  firm  and  compact,  with  a  blackish  color, 
to  varieties  of  brown  color  and  composed  distinctly  of 
vegetable  fragments. 

Peat  is  a  vegetable  accumulation  formed  at  the 
present  surface,  from  mosses,  leaves,  and  sticks,  and 
is  not  yet  consolidated  into  the  condition  of  a  coal. 


188     Walks  and  Talks  in  the  Geological  Field. 

It  is  used,  however,  extensively  as  a  fuel,  especially 
on  the  continent  of  Europe,  where  the  traveler  may 
see  it  cut  out  in  blocks  and  piled  up  like  bricks  dry- 
ing in  the  sun.  The  city  of  Paris  is  warmed  chiefly 
by  peat.  Many  efforts  have  been  made  in  America 
to  reduce  peat  to  a  cheap  and  efficient  fuel ;  but  for 
the  present,  it  is  unable  to  compete  with  our  other 
natural  combustibles. 

Mode  of  Coal  occurs  in  strata — not  in  veins— interbedded 
occurrence  witn  sedimentary  rocks.  Shales,  clays,  and  sand- 
stones exist  extensively  in  Coal  Measures  ;  and  in 
some  regions,  limestones  are  interstratifled.  The 
latter  contain  fossil  shells,  and  are  manifestly  of 
marine  origin.  The  coal  must  have  been  produced 
on  the  land.  Some  of  the  clays  are  apparently  the 
soil  in  which  the  vegetation  grew,  since  the  roots  are 
found  extending  into  them.  The  shales  were  de- 
posited in  quiet,  muddy  waters,  within  easy  reach  of 
the  products  of  the  land,  since  they  contain  immense 
quantities  of  fronds  and  other  vegetable  matters, 
generally  in  a  fine  state  of  preservation. 
Method  of  ^n  regi°ns  somewhat  disturbed,  like  Pennsylvania, 
mining,  the  strata  of  coal  make  outcrops  like  limestones, 
shales,  and  sandstones.  Mining  is  then  prosecuted 
from  the  "crop"  by  carrying  an  excavation  or  drift 
along  the  slope  of  the  coal  stratum.  If  possible,  the 
place  is  so  selected  that  the  slope  may  ascend  from 
the  mouth,  so  that  the  water  reached  may  flow  out 
spontaneously.  If  this  is  not  practicable,  then  pump- 
ing must  be  resorted  to,  and  this  sometimes  becomes 
enormously  expensive.  In  regions  where  the  strata 
repose  in  nearly  horizontal  positions,  the  underlying 
coal  beds  are  reached  through  vertical  shafts.  In 


Monsters  of  a  Buried  World.  189 

such  cases,  pumping  machinery  is  essential.  Not 
unfrequently,  one  shaft  is  extended  down  to  a  second 
or  third  bed  of  coal.  In  any  case,  after  the  coal  is 
reached,  chambers  or  galleries  are  excavated  in  rec- 
tangular directions  in  the  bed.  The  roof  is  supported 
by  large  blocks  of  coal  left  undisturbed.  After  most 
of  the  coal  has  been  thus  removed,  the  supporting 
blocks  are  worked  out  successively,  and  the  roof  of 
the  mine  may  be  permitted  to  fall  in. 


XXVII.     MONSTERS  OF  A  BURIED  WORLD. 

EXTINCT   QUATERNARY  MAMMALS. 

"MR.  JOHN  SMITH,  of  the  town  of  Sharon,  in 
digging  a  ditch  to  drain  a  swamp  on  his  farm,  ex-  of  mam- 
humed  some  very  large  bones  which  must  have  lain  mals  from 
buried  for  many  thousand  years.    They  appear  to  be 
the  bones  of  a  giant.    They  will  be  offered  to  the  Uni- 
versity for  sale. ' ' 

"Mr.  Peter  Jones  discovered  last  week  in  a  peat 
bed,  a  nearly  complete  skeleton  of  some  antediluvian 
monster.  Mr.  Jones  will  have  the  skeleton  set  up  as 
soon  as  possible,  and  will  then  start  on  a  tour  of 
exhibition.  He  feels  confident  there  is  a  fortune  in 
these  bones." 

The  above  are  samples  of  paragraphs  frequently 
appearing  in  the  newspapers.  They  indicate  that  the 
peat  bogs  of  our  country  contain  many  relics  of 
beings  no  longer  in  existence,  and  no  longer  remem- 
bered. 

Such  relics  have  been  discovered  also,  in  the  Old 
World,  and  former  generations  have  been  strongly 


190      Walks  and  Talks  in  the  Geological  Field. 

inclined  to  attribute  them  to  a  race  of  giants  now  ex- 
tinct. An  intelligent  inspection  of  these  bones, 
however,  shows  that  they  never  belonged  to  human 
giants,  and  can  not,  therefore,  be  the  remains  or  tes- 
timonials of  the  "giants"  of  antediluvian  times. 
Modern  science  has  shown  that  they  belonged  to 
elephant-like  creatures,  of  two  different  genera.  One 
of  these  was  the  true  Elephant,  and  the  other  is 
known  as  Mastodon.  The  Mastodon  has  not  been 
seen  during  historic  times  ;  but  we  conclude  from  the 
relics  remaining,  that  it  was  very  similar  to  the  Ele- 
phant, and  differed  chiefly  in  the  structure  of  the 
grinding  teeth.  The  molars  of  the  Elephant  are 
enormously  large,  and  only  one  is  in  use  in  each  jaw 
on  each  side,  at  one  time.  It  may  be  regarded,  how- 
ever, as  a  compound  tooth,  consisting  of  ten  or 
twenty  simple  flat  teeth  standing  closely  and  firmly 
compacted  together  by  means  of  a  substance  called 
cement.  The  molar  of  the  Mastodon  has  more  the 
appearance  of  an  ordinary  tooth,  with  three,  four,  or 
five  transverse  prominences,  rising  like  steep  and  fur- 
rowed ranges  of  mountains.  It  is  smaller  than  the 
elephant  molar ;  and  three  or  four  were  in  use  at  once 
on  each  side  of  each  jaw. 

similar         Commonly,  as  already  indicated,  the  bones  of  the 
remains     extinct  Elephant  and  Mastodon  have  been  discovered 

from  mod- 
ified Drift,  in  peat  deposit.    Such  deposits  are  explained  in  Talk 

VIII,  and  rest  upon  the  top  of  the  Drift,  and  are 
more  recent  than  the  Drift.  But  in  Europe  bones  of 
the  Elephant  have  sometimes  been  met  with  in  the 
modified  Drift.  They  also  occur  in  many  caverns 
which  are  believed  to  have  been  occupied  by  wild 
beasts  in  the  Drift  epoch.  We  may  conclude,  there- 


Monsters  of  a  Buried  World.  191 

fore,  that  the  Elephant  came  down  from  the  Tertiary 
Age.  Indeed,  we  shall  see  from  the  facts  to  be  stated 
in  the  next  Talk,  that  both  Elephant  and  Mastodon 
began  to  exist  before  the  Quaternary  Age. 

Some  very  remarkable  facts  have  come  to  light  Mam 
from  northern  Siberia.  That  inhospitable  region 
was  once  a  home  for  Elephants.  More  than  a  hun- 
dred years  ago,  not  only  their  ivory,  but  their  car- 
casses were  known  to  exist  in  Siberia  imbedded  in 
solid  ice.  The  first  discovery  was  on  the  borders  of 
the  Aleseia  River,  which  flows  into  the  Arctic  Ocean 
beyond  the  Indigirka.  The  body  was  still  standing 
erect,  and  was  almost  perfect.  The  skin  remained  in 
place,  and  the  hair  and  fur  were  still  attached  in 
spots.  In  1772,  the  body  of  a  perfect  two-toed  rhi- 
noceros covered  with  hair,  was  found  preserved  in 
frozen  gravel  near  the  Vilhoui  or  Wiljui,  a  tributary 
of  the  Lena,  in  latitude  64°.  The  head  and  feet  of 
this  animal  are  preserved  in  St.  Petersburg.  The 
most  celebrated  discovery  was  made  in  1799.  A 
Tungusian  fisherman  named  Schumachoff  was  ex- 
ploring along  the  coast  of  the  frozen  ocean  for  ivory. 
Near  the  mouth  of  the  Lena  he  noticed,  in  a  huge 
block  of  clear,  glacier  ice,  a  dark,  strange  object 
deeply  imbedded.  His  half  savage  curiosity  was  not 
strong  enough  to  lead  him  to  undertake  the  work  of 
exploration.  In  1801  the  melting  of  the  ice  had  ex- 
posed a  portion  of  the  carcass.  It  was  a  beast  like 
those  whose  ivory  lay  strewn  along  those  frozen 
shores.  In  1804,  the  Tungusian  was  able  to  remove 
the  tusks.  They  weighed  three  hundred  pounds, 
and  he  disposed  of  them  for  fifty  rubles,  to  an  ivory 
merchant.  In  1806,  Mr.  Adams,  who  was  collecting 


192     Walks  and  Talks  in  the  Geological  Field. 

for  the  Imperial  Museum  at  St.  Petersburg,  found 
the  carcass  still  on  the  shore,  but  greatly  mutilated. 
It  appeared  that  the  Yakutski  had  actually  regaled 
their  dogs  upon  the  flesh  ;  and  bears,  wolves,  wolver- 
ines and  foxes  had  gladly  feasted  upon  it !  Thus  this 
priceless  relic  of  a  prehistoric  world  was  allowed  to 
waste  away.  But  it  was  not  completely  lost  to 
science ;  for  except  one  fore-leg,  the  skeleton  re- 
mained perfect.  A  large  part  of  the  skin  had  also 
escaped  destruction,  together  with  one  of  the  ears, 
which  still  retained  its  characteristic  tuft  of  hairs. 
The  skin  was  of  a  dark  tint  and  was  covered  with 
reddish  wool  an  inch  in  length,  interspersed  with 
reddish-brown  hairs  four  inches  long,  and  sparser 
black  bristles  twelve  to  sixteen  inches  long.  Every- 
thing of  value  was  now  collected,  including  more 
than  thirty  pounds  of  fur;  the  tusks  were  repurchased, 
and  the  whole  was  transported  to  St.  Petersburg, 
where  the  mounted  specimen  at  present  stands,  in 
the  Imperial  Museum.  This  individual  was  nine 
feet  high  and  sixteen  feet  long,  exclusive  of  the 
tusks. 

Other  discoveries  have  been  made  more  recently. 
In  1843,  a  mammoth  was  found  by  Middendorf  in  so 
perfect  a  state  that  the  bulb  of  the  eye  is  still  pre- 
served in  the  museum  at  Moscow.  In  1858,  a  mam- 
moth was  discovered  in  the  delta  of  the  Lena, 
twenty-three  miles  from  Sagastyr.  The  head  and 
tusks  had  already  been  removed  by  a  Russian  mer- 
chant. The  Yakuts  soon  after  the  discovery  took  a 
leg,  several  ribs  for  making  spoons,  parts  of  the  skin 
for  straps,  and  fat  for  painting  their  sledges.  The 
body  was  reported  in  1884  as  lying  on  its  side  in  the 


Monsters  of  a  Buried  World.  193 

lower  part  of  a  crag  of  alluvial  deposits  thirty  feet 
high.  Dr.  Bunge,  who  undertook  to  excavate  on  the 
spot,  found  the  material  a  frozen  mass  of  snow  "  as 
hard  as  sugar."  Still  another  mammoth  was  dis- 
covered in  1878  on  the  Moloda  River,  a  tributary  of 
the  Lena,  which  it  joins  on  the  left  thirty  miles 
above  Siktyakh.  We  shall  have  to  inquire,  hereafter, 
what  was  the  nature  of  the  catastrophe  which  buried 
these  huge  quadrupeds  in  their  common  tomb  of  ice. 
The  same  mammoth  dwelt  in  Alaska.  His  tusks  are 
extensively  sought  and  sold  for  ivory. 

The  great  original  skeleton  standing  in  the  Museum 
at  St.  Petersburg  was  duplicated  at  Stuttgart  under  tioD  oi 
the  direction  of  Dr.  Fraas,  from  various  bones  col-  moth] 
lected  from  different  parts  of  Europe.  Dr.  Fraas, 
from  samples  of  skin  and  hair  still  existing,  ventured 
to  give  the  extinct  mammoth  a  complete  restoration. 
Professor  Ward,  the  great  museum-builder  of  America, 
saw  this  monster  of  mammoths  standing  in  the  Mu- 
seum at  Stuttgart  and  purchased  it.  Transporting  it 
to  Rochester,  he  reared  a  duplicate,  which  stood  for 
months  in  the  Ward  Museum,  where  I  had  the  oppor- 
tunity of  subjecting  the  creature  to  a  careful  study. 
Let  us  go  back  and  repeat  the  visit. 

"  As  we  enter  the  door  of  the  building  which  has 
been  erected  for  the  accommodation  of  this  antedilu- 
vian, a  dark  mountain  of  flesh  rises  before  us.  We 
had  gauged  our  apprehension  to  the  familiar  bulk  of 
the  elephant,  but  here  the  eye  must  be  lifted  to  a 
higher  altitude  ;  the  whole  thought  must  swell  to 
take  in  the  idea  of  the  towering  form  which  looms 
above  us  and  frowns  darkly  and  severely  down  upon 
us.  The  monster's  brow  rises  like  some  old  granite 


194     Walks  and  Talks  in  the  Geological  Field. 

dome,  weather-beaten  and  darkened  by  the  lapse  of 
geologic  ages.  Two  winding  streams  of  ivory  descend 
like  glaciers  from  the  base  of  the  dome,  while  the 
corrugated  and  beetling  proboscis  swells  between 
them  like  the  embattled  crest  which  divides  two 
Alpine  glacier-torrents.  Behind  expands  and  uprises 
the  mountain  mass  of  which  these  are  the  accessories. 
"All  this  dark  and  towering  mass  is  conscious. 
There  are  eyes  which  open  on  us  and  take  cognizance 
of  our  movements ;  there  are  ears  which  take  in  the 
sounds  of  our  voice.  This  creature  contemplates  us. 
"He  stands  sixteen  feet  in  height.  His  extreme 
length  is  twenty-six  feet,  and  the  distance  between 
the  tips  of  his  tusks  is  fourteen  feet.  His  body  is 
thirty  feet  in  circumference  close  to  the  skin.  The 
sole  of  his  foot  is  three  feet  in  diameter.  His  tusks 
are  fourteen  feet  long  and  one  foot  in  diameter  at 
base.  Between  his  short,  post-like  fore-legs  a  man  can 
stand  upright  with  his  hat  on,  without  touching  the 
animal's  body.  The  whole  exterior  is  clothed  with 
dark  shaggy  hair,  quite  unlike  the  modern  elephants, 
and  under  the  throat  it  attains  a  length  of  twelve  to 
fifteen  inches." 

Other  Europe,  Asia,  and  America  had  their  Mammoth 

and  Mastodon  in  the  Quaternary  Age;   and   their 
mains        bones  and  carcasses  still  lie  preserved  in  Drift  depos- 
£°tf  the     its  to  testify  to  their  existence.    South  America,  how- 
ever, had  its  Megatherium,  its  Mylodon,  its  Scelido- 
therium,  and  other  strange  giants  of  the  order  known 
as  Edentates.    These  have  been  found  imbedded  in 
the  "  Pampean   Formation,"   which   extends   from 
Brazil   nearly  to   the   Straits   of   Magellan.     It   is 
mostly  a  level  and  sparsely  wooded  plain,  covered  by 


Monsters  of  a  Buried  World.  195 

a  rich  soil  underlaid  by  gravel  and  sand.  Numerous 
marine  remains  indicate  that  it  was  covered  by  the 
sea  during  a  period  geologically  recent.  In  this  for- 
mation have  been  found  the  ponderous  bones  of  a 
colossal  ground-sloth,  now  known  as  Megatherium.  Megatht 
The  first  relics  were  discovered  in  1789,  near  the  city  rium- 
of  Buenos  Ayres.  A  nearly  complete  skeleton  was 
sent  to  Madrid,  where  it  still  stands,  the  chief  scien- 
tific attraction  of  the  Spanish  capital.  Through  va- 
rious other  discoveries,  entire  skeletons  have  been  re- 
constructed, the  most  perfect  of  which  stands  in  the 
British  Museum.  Plaster  copies  of  this  have  been 
made  under  the  direction  of  Professor  Ward,  and  the 
Megatherium  is  now  a  familiar  sight  in  American 
museums. 

This  was  one  of  the  most  anomalous  creatures  of 
the  strange  past.  It  was  one  of  the  last  of  the  great 
"  comprehensive  types  "  which  appeared  in  the  prog- 
ress of  the  history  of  life,  and  of  which  you  will  hear 
much,  as  we  trace  this  history  backward.  It  was 
studied  by  the  great  Cuvier,  among  many  others,  and 
he  first  revealed  its  true  affinities.  Some  regarded 
it  as  tree-inhabiting  ;  some  thought  it  subterranean  ; 
Owen  decided  that  it  must  have  lived  upon  the 
ground.  As  represented  by  Hawkins,  it  stands  semi- 
erect,  resting  on  its  massive  hinder-extremities,  with 
auxiliary  support  from  a  vast  pillar-like  tail,  with 
anterior  extremities  clasping  the  trunk  of  a  tree  and 
relatively  diminutive  head  and  tapir-like  snout 
turned  upward  toward  the  foliage  which  probably 
served  as  its  food. 

The  length  of  the  skull  is  thirty-one  inches  ;  its 
breadth,  eighteen.  The  brain-box  is  very  small  for 


196      Walks  and  Talks  in  the  Geological  Field. 

the  bulk  of  the  animal.  The  molar  teeth  have  hol- 
low fangs  for  continuous  growth,  as  in  the  sloth  and 
many  modern  rodents.  The  spinal  column  is  15  J 
feet  long.  The  circumference  of  the  skeleton  at  the 
eighth  rib  is  ten  feet.  The  scapula  is  a  vast  expanse 
of  bone  two  and  a  half  feet  long.  The  distal  (far- 
ther) end  of  the  humerus  is  13  inches  wide,  while  that 
of  the  elephant  is  only  one  fourth  as  great.  The 
pelvis  is  a  mountain  of  bone.  It  is  far  more  massive 
than  that  of  the  elephant  or  any  known  animal,  liv- 
ing or  extinct.  Its  extreme  breadth  is  upward  of 
five  feet — that  of  the  Asiatic  elephant  being  sixteen 
inches  less.  The  socket  for  the  head  of  the  femur 
presents  a  surface  of  44  square  inches,  which  is  200 
times  the  same  surface  in  the  pigmy  shrew-mouse. 
The  thigh  bone,  in  the  Mastodon  and  Elephant,  ap- 
pears weak  and  slender  compared  with  that  of  the 
Megatherium.  It  is  two  feet  two  inches  in  circum- 
ference at  the  largest  part.  The  hind  legs  look  more 
like  columns  for  the  support  of  a  bridge  than  like  or- 
gans for  locomotion.  The  circumference  of  the  tail 
at  its  largest  part  was  six  feet. 

We  have  to  imagine  this  gigantic  framework 
clothed  with  flesh  and  instinct  with  life.  It  towers 
before  us  a  huge,  ungainly  beast,  eighteen  feet  in 
length  and  eight  feet  high,  having  a  tapir-like  head, 
an  elephantine  body,  and  hind  feet  and  tail  which 
find  no  match  in  geologic  or  historic  time.  Such 
super-mammoth  haunches,  nearly  six  feet  across ; 
such  singular,  half-hoofed,  half-clawed  extremities ; 
so  slow  and  awkward  in  his  movements  ;  so  stupid  in 
look— he  seems  the  lord  of  the  Pampas.  His  thick 
and  callous  hide  is  scantily  clothed  with  coarse,  stiff 


Monsters  of  a  Buried  World.  197 

hair.  He  seeks  his  food  from  the  leaves  of  the  forest. 
Other  leaf-eaters  possess  various  provision  for  secur- 
ing their  food.  The  elephant  is  furnished  with  an 
elongated  proboscis.  The  giraffe  is  uplifted  on  fore- 
legs of  extraordinary  length,  supplemented  by  a 
neck  of  length  equally  extraordinary,  and  lips  and 
tongue  co-ordinated  with  other  parts  of  his  outfit. 
The  sloth  ascends  the  tree  and  places  himself  in  the 
midst  of  the  foliage  on  which  he  must  subsist.  Our 
Megatherium  has  none  of  the  provisions  of  the  ele- 
phant or  giraffe,  and  is  too  ponderous  to  be  borne  by 
the  branches  of  a  tree.  He  raises  himself  in  a  semi- 
erect  attitude,  supported  by  that  tripod  formed  of  tail 
and  hind  feet,  and  reaches  with  his  fore-limbs  to  the 
foliage  and  gathers  it  in.  When  the  supply  falls 
short,  he  employs  his  powerful  effodient  feet  to  hurl 
the  earth  from  the  roots  of  the  tree,  and  bring  it 
down  by  his  colossal  strength.  Then  he  stretches 
himself  alongside  of  the  prostrate  tree  and  gathers 
its  foliage  at  his  leisure. 

These  are  samples  of  the  relics  of  the  Quaternary  North 
Age.    In  North  America  are  found  remains  of  a  pig-  American 
like  creature,  a  gigantic  beaver,  and  some  Edentates. 
They  are  found  imbedded  in  sand  and  fluviatile  de- 
posits, accumulated,  like  the  elephant-bearing  peats, 
after  the  Drift.    The  bowlder  Drift  is  mostly  desti- 
tute of  organic  remains.     Probably  the  severity  of 
the  temperature  and  the  prevalence  of  ice  rendered 
animal  life  impossible. 


198      Walks  and  Talks  in  the  Geological  Field. 


XXVIII.     THE  CEMETERIES  OF  THE  BAD 
LANDS. 

TERTIARY    FOSSILS. 

The  Bad  THE  "Bad  Lands  "in  the  dialect  of  the  trapper 
and  Indian,  are  regions  unfavorable  to  the  pursuit 
of  their  occupations  ;  as  the  snow-covered  slopes  of 
the  Alps  are  Monts  maudits  (cursed  mountains)  in 
Savoy,  and  an  unavailable  ridge  in  the  Pyrenees  is 
Monte  maladetta  to  the  Spaniard.  The  Bad  Lands 
of  the  United  States  are  underlaid  by  Tertiary  strata 
which  have  been  worn  and  wasted  in  innumerable 
fantastic  shapes,  and  excavated  on  so  vast  a  scale  as 
to  expose  to  view  the  relics  of  the  creatures  buried 
beneath  the  rubbish  of  hundreds  of  thousands  of 
years.  In  order  of  succession  these  strata  lie  further 
than  the  Quaternary  deposits  from  the  completed 
surface.  Still,  there  are  extensive  regions  where 
nothing  more  modern  covers  the  wastes  of  the  Bad 
Lands. 

Tertiary        Inspect  the  rocks  of  some  Tertiary  district ;  we  are 
strata  in     pre^ty  sure  to  find  them  horizontal  or  nearly    so. 

America.    r 

Along  the  Atlantic  and  Gulf  coasts  they  slope  gently 

toward  the  sea.  In  some  parts  of  the  Pacific  coast, 
the  Tertiary  strata  have  been  tilted  to  high  angles 
and  subjected  to  metamorphic  action.  In  the  interior 
of  the  continent  they  generally  lie  in  positions  nearly 
horizontal.  Tertiary  strata  which  slope  down  to  the 
sea  and  under  it — or  once  had  such  a  slope — are  of 
marine  origin,  and  contain  relics  of  marine  popula- 


The  Cemeteries  of  the  Bad  Lands.  199 

tions.  In  the  interior,  we  find  the  fossil  remains 
mostly  those  of  fresh  water  and  the  land.  In  some 
of  the  deepest  Tertiary  of  the  interior,  the  aquatic 
forms  are  brackish-water  species  ;  and  those  from 
the  lowest  beds  are  sometimes  salt  water  species. 
These  facts  are  important  in  setting  in  order  the  his- 
tory of  Tertiary  times. 

Let  us  visit  one  of  these  desert  spaces  of  the  con- 
tinent.  We  leave  the  valley  of  the  upper  Missouri  tionofthe 

Bad 

and  travel  overland  across  plains  parched  by  drouth  Lands, 
and  clothed  only  with  scattered  sage  brush.  The 
buffalo  is  not  found  grazing  here  ;  birds  and  insects 
avoid  the  herbless  waste.  Our  mules  toil  on  in  the 
withering  heat  of  summer,  and  reach  with  weariness 
the  border  of  a  shrunken  stream  on  which  to  en- 
camp. With  patient  progress  we  arrive  at  a  region 
which  shows  symptoms  of  a  change  of  scene.  Ahead, 
appears  a  less  monotonous  landscape.  Some  breaks 
in  the  surface  are  revealed.  There,  in  the  distance, 
are  forms  which  remind  us  of  architectural  struc- 
tures. We  seem  to  see  gables  and  towers. 

We  press  on.  The  illusion  dissolves.  Before  us 
stretches  a  wide  excavation,  down  into  the  forma- 
tions underneath.  Where  are  the  materials  re- 
moved from  this  emptied  basin?  What  power 
plowed  up  the  strata  and  carted  away  the  debris'! 
We  come  to  the  brink  of  the  basin— a  vast  rock  basin 
cut  through  beds  of  horizontal  shales  and  soft  lime- 
stones. The  sloping  walls  have  been  worn  for  a 
thousand  centuries  by  the  rills  formed  from  the  win- 
ter rains.  The  fluted  columns  have  been  grooved  by 
water.  The  salient  abutments  have  been  chiseled  by 
the  storm. 


200     Walks  and  Talks  in  the  Geological  Meld. 

The  rock-layers  are  visible  all  around  the  depres- 
tery.  siOn.  We  descend  to  the  floor  and  trace  their  con- 
tinuity from  side  to  side.  Each  layer  was  once  a  lake 
bottom.  But,  behold  the  relics  of  a  former  population 
scattered  over  this  floor.  Here  are  the  skulls  of 
sheep-like  creatures  which  are  also  pig-like  ;  the  car- 
apaces of  turtles  unlike  any  turtles  living  ;  the  shin- 
bones  of  rhinoceroses  which  no  longer  roam  in  the 
jungle.  We  turn  our  eyes  again  to  the  rocky  layers, 
and  lo  !  like  shelves  of  a  vast  cabinet,  they  hold  the 
specimens  which  illustrate  a  fauna  passed  away— a 
classified  cabinet,  where  each  shelf  is  stored  with  the 
relics  of  its  epoch,  and  the  lower  shelves  are  filled 
with  the  souvenirs  of  the  older  time. 

Life  once  thrilled  through  all  these  torpid  frames. 
These  were  conscious  creatures.  These  were  joyous 
creatures  walking  on  the  green  earth.  These  were 
beings  which  inhaled  the  vital  air,  and  basked  in  the 
life-giving  sunlight,  and  enjoyed  each  other's  society. 
They  fed  on  the  productions  of  the  forest  and  the 
glade.  They  wandered  over  a  land  which  was  to  be 
Dakota  and  Nebraska.  They  slaked  their  thirst  at 
the  border  of  the  wide  lake  ;  they  cooled  themselves 
in  its  waters,  and  sometimes  sported  with  its  waves. 
Death  came  to  them,  as  to  their  thousands  of  pred- 
ecessors—as it  comes  to  us.  They  were  mired  in  a 
slough;  they  were  hunted  in  a  jungle;  they  lay 
down  in  the  shade  of  a  friendly  tree  ;  some  force  of 
nature  bore  them  to  their  burial.  The  lake  was  their 
tomb,  and  the  lake  preserved  its  trust. 

Localities      The  formation  in  which  these  creatures  are   en- 
ofTertmry  tombed  stretches  from  eastern  Nebraska  to  Laramie, 

deposits : 

and  from  the  Cheyenne  River,  Dakota,  into  north- 


The  Cemeteries  of  the  Bad  Lands.  201 

western  Kansas.  It  is  called  Neocene  or  Upper  Ter-  Neocene 
tiary.  Other  smaller  areas  of  the  same  exist  in 
Colorado,  Wyoming,  Montana,  and  Nevada.  A  very 
large  area  exists  also  in  Oregon  and  Washington. 
Upper  Tertiary  strata  also  border  the  Gulf  of  Mex- 
ico, from  Mobile  to  the  Eio  Grande,  stretching  in- 
land a  hundred  miles,  and  up  the  valley  of  the 
Mississippi  to  Cairo.  Near  the  gulf  shore,  however, 
and  along  the  delta  of  the  Mississippi  the  Neocene  is 
concealed  by  alluvial  deposits.  Neocene  Tertiary 
stretches  along  the  Atlantic  coast  also,  from  Montauk 
Point  to  the  southern  part  of  Florida — from  Charles- 
ton southward,  however,  overlaid  next  the  shore  by  a 
narrow  belt  of  alluvial  or  recent  deposits.  There  are 
few  remains  of  land  animals  in  the  marine  Tertiary  ; 
but  shells  and  corals  are  plentiful.  A  majority  of 
them  belong  to  the  same  species  as  are  now  living 
in  the  nearest  parts  of  the  Atlantic.  Near  Charles- 
ton, however,  have  been  found  the  remains  of  a 
horse  more  resembling  the  domestic  horse  than  those 
in  the  Bad  Lands.  Indeed,  the  Carolina  horse  was 
extremely  like  the  species  long  afterward  brought  to 
America  from  Europe.  As  this  species  is  not  known 
in  the  Neocene  of  Europe,  the  indications  are  that  it 
lived  in  America  before  it  did  in  Europe.  That  is, 
the  late  Tertiary  horse  originated  in  America  ;  after- 
ward found  its  way  to  Europe  and  Asia,  and  finally 
was  brought  back  to  the  New  World  by  immigrants 
in  the  sixteenth  century.  Almost  the  same  story  has 
to  be  told  of  the  camel. 

But  there  are  older  Tertiary  deposits  called  Eocene,  Eocene 
which  means  the  "  dawn  of  the  recent,"  because  the 
marine  shells  found  in  them  contain  a  few   recent 


202      Walks  and  Talks  in  the  Geological  Field. 

species,  and  only  a  few,  while  the  shells  of  all  older 
formations  are  specifically  distinct  from  any  now 
living.  The  Eocene  strata  are  seen  passing  under  the 
Neocene  all  along  the  Atlantic  and  Gulf  border,  and 
up  the  delta  of  the  Mississippi.  When  these  strata 
were  deposited,  the  Atlantic  and  Gulf  extended  to  the 
inland  limit  of  the  Eocene.  The  valley  of  the  Missis- 
sippi as  far  as  Cairo  was  under  the  Gulf — a  bay 
setting  northward  to  Cairo  from  about  the  latitude  of 
Montgomery,  Alabama.  In  this  sea  sported  the  great 
Keugiodon.Zeu9l°d°n  — a  vertebrate  of  whale-like  nature,  but 
serpent-like  form,  which  on  the  first  discovery  of  its 
remains,  was  supposed  to  be  a  real  sea-serpent.  Its 
length  was  sixty  to  eighty  feet.  A  skeleton  dug 
up  in  Clarke  County,  Alabama,  by  Dr.  Koch,  was 
named  Hydrarchos— king  of  the  hydras— and  was 
formerly  exhibited  in  Barnum's  Museum,  New  York 
— afterward  sent  to  London,  where  Professor  Richard 
Owen  determined  its  true  nature.  The  vertebrae 
of  this  curious  whale  are  found  strewn  over  the  corn 
and  cotton  fields  of  southern  Alabama.  I  have  seen 
them  used  for  andirons  in  the  rude  fireplaces  of  the 
country,  and  set  for  steps  of  a  stile  over  the  front 
fence  of  the  door  yard. 

Other  The  region  underlaid  by  the  Eocene  abounds  in 

fossil"6  sneUg  and  corals  and  fish-teeth  washed  out  by  the 
weather.  The  strata  are  mostly  friable,  and  some 
almost  incoherent.  The  rivers  and  creeks  have  ex- 
cavated deep  channels,  and  thus  caused  many  fine 
exposures.  The  most  celebrated  river  bluffs  in  the 
Alabama  and  Mississippi  Eocene  are  at  Claiborne,  St. 
Stephens,  and  Vicksburg.  All  these  localities  abound 
in  fossils,  but  especially  the  first  and  last  named ; 


The  Cemeteries  of  the  Bad  Lands.  205 

and  the  fossils  exist  in  a  perfect  state  of  preservation. 
At  St.  Stephens  we  find  the  "White  Limestone" 
which  incloses  the  remains  of  Zeuglodon.  Eocene 
fossils  are  found  in  great  abundance  also,  along  all 
the  creeks  and  ravines,  and  by  the  roadsides. 

For  many,  the  remains  inclosed  in  the  fresh-water  Fresh- 
Eocene  of  our  western  territories  possess  still  greater  water 

Eocene  of 
interest ;  for  they  are  the  bones  and  teeth  of  strange  Wyoming, 

and  often  gigantic  quadrupeds  which  dwelt  on  the  ete- 
land.  In  the  southwestern  part  of  Wyoming,  and 
extending  south  to  the  Uinta  Mountains,  is  a  great 
expanse  of  such  strata.  On  the  south  of  the  Uinta 
Mountains  is  another,  extending  southeastward  into 
Colorado,  and  south  and  southwestward  into  Central 
Utah.  Another  vast  Eocene  region  stretches  from 
southern  Colorado  into  New  Mexico.  It  is  chiefly 
from  the  Eocene  of  Wyoming  that  Professor  Marsh 
obtained  the  mammalian  bones  which,  during  many 
years  back,  he  has  described  for  the  astonishment  of 
the  world.  Some  very  unique  material,  however, 
was  procured  in  Oregon.  The  equal  work  performed 
by  Professor  Cope,  has  also  been  based  partly  on 
specimens  from  Wyoming,  but  more  largely  011 
material  from  New  Mexico  and  Texas.  These  wide, 
western  regions  pastured  herds  of  herbivores  in  the 
early  Tertiary  time,  as  they  have  continued  to  do 
down  to  the  invasion  of  the  locomotive  and  the 
transformations  of  civilization. 
I  cannot  undertake  to  convey  to  your  comprehen-  Tne  ^ 


sion.  in  a  few  lines,  any  adequate  conception  of  the  cen€ 

mals  are 
aspects  and  characters  of  these  long  extinct  beings.  of  <.  c^. 

If  we  speak  only  of  mammals,  we  can  say  that  they  prehensive 
generally   differed   widely — often   grotesquely — from 


206      Walks  and  Talks  in  the  Geological  Meld. 

any  forms  now  living.  It  was  then  near  the  begin- 
ning of  mammalian  development  on  the  earth.  Still 
those  creatures  presented  unmistakable  resemblances 
to  modern  mammals,  in  all  fundamental  respects.  If 
there  were  no  elephants,  there  were  the  Bronto- 
therium  and  Dinoceras  and  Tinoceras,  and  especially 
in  the  Old  World,  the  Dinothcrium,  which  seemed 
like  uncouth  and  undeveloped  pachyderms  trying  to 
become  proboscidians.  But  the  Brontotherium  had 
no  tusks,  no  trunk,  no  elephantine  molars.  The 
"  comprehensive"  character  of  these  and  other  early 
mammals  was  the  most  interesting  fact;  but  I  re- 
serve more  particular  mention  for  a  later  opportunity. 


XXIX.     LESSON  FROM  A  LUMP  OF  CHALK. 

MESOZOIC  BOCKS  AND  FOSSILS. 

Thechem-  THIS  white  lump,  soft  enough  to  be  cut  with  a 
istry  of  knife,  effervesces  very  briskly  when  any  strong  acid  is 
applied  to  it.  Even  strong  vinegar  causes  the  forma- 
tion of  a  multitude  of  small  bubbles.  Effervescence 
is  caused  by  the  escape  of  some  gas.  Almost  always, 
the  gas  is  carbonic  acid,  or  as  we  now  say,  carbon 
dioxide.  Chalk  is  a  compound  of  this  and  calcium. 
The  latter  is  familiar  in  the  form  of  lime.  Carbonic 
acid  is  feeble,  and  when  the  strong  acid  is  applied  to 
the  chalk,  it  drives  off  the  carbonic  acid,  and  takes 
possession  of  the  calcium  for  itself,  forming  a  differ- 
ent compound.  The  carbonic  acid  when  freed  from 
combination,  resumes  its  gaseous  form.  It  therefore 
swells  up,  and  mixed  with  the  water  of  the  strong 
acid,  produces  the  bubbles  which  constitute  efferves- 


Lesson  from  a  Lump  of  Chalk.  207 

cence.     Chalk,  however,  has  essentially   the   same 
constitution  as  limestone  and  marls. 

If  we  pulverize  some  of  this  chalk  and  examine  the  structure 
particles  with  a  microscope,  we  discover  that  the  and  origin, 
greater  part  consists  of  minute  shells  or  shell-frag- 
ments. Indeed,  here  is  Globigerina  again  !  We 
found  Globigerina  in  our  "Walk  Under  the  Sea" 
(Talk  IX.).  Billions  upon  billions  of  these  minute 
shells  accumulated  together,  have  formed  that  white 
ooze  which  overspreads  so  large  a  part  of  the  deep 
sea-bottom.  If  some  of  that  ooze  should  be  com- 
pressed and  dried,  it  would  be  exceedingly  like  chalk. 
There  is  little  doubt  that  the  real  chalk  so  abundant 
in  Europe,  was  originally  a  white  ooze  in  the  bottom 
of  the  ocean,  when  much  of  Great  Britain  and  the 
continent  was  buried  in  its  waters.  What  we  found 
in  the  depths  of  the  Atlantic  must  be  a  modern 
picture  of  the  condition  of  the  ancient  ocean  which 
covered  Europe  some  millions  of  years  ago.  The 
bottom  of  the  Atlantic  was  then  the  bottom  of  the 
Atlantic.  Its  present  condition  has  been  perpetuated 
from  the  Cretaceous  Age ;  and  many  of  the  minute 
forms  accumulating  there  to-day  are  generically  iden- 
tical with  the  forms  which  lived  when  the  chalk  was 
a  sea-bottom. 

A  few  years  ago,  when  these  things  were  first  ascer-  •Dogma  of 
tained,  and  the  first  announcement  was  made  that  "tnecon- 
the  fossil  forms  of  the  chalk  were  still  living  in  the 
Atlantic,  a  triumphant  outcry  was  made  through  the 
newspapers  by  the  ignorant  enemies  of  geological 
science.  It  has,  since  Cuvier,  always  been  a  funda- 
mental doctrine  in  geology,  that  the  earth's  surface 
has  been  occupied  by  a  succession  of  populations 


208     Walks  and  Talks  in  the  Geological  Meld. 

showing  progressive  advancement  toward  the  mod- 
ern aspects  of  the  world.  But  "  here,"  they  affirmed, 
"we  find  no  change  since  the  chalk.  The  founda- 
tion of  geology  is  disrupted.  The  so-called  science  is 
a  baseless  mass  of  '  theories '  !  There  is  no  sound 
evidence  of  the  great  age  of  the  world.  The  'days' 
of  Genesis  were  twenty-four  hours  long.  Hurrah !" 
The  true  The  life  of  geology  was  scarcely  conscious  of  a  rip- 
expiana-  pie.  The  old  principles  rest  firmly.  The  facts  cited, 
sentex_  instead  of  proving  destructive,  confirm  another  doc- 
istenceof  trine  even  more  dreadful  than  that  of  successive 
faunas  an(l  great  antiquity — the  doctrine  of  correla- 
tion of  organic  structure  with  environment.  Faunas 
change  as  the  physical  surroundings  change;  but  if  the 
physical  surroundings  remain  changeless,  the  faunas 
remain  changeless.  Down  in  the  deep  sea,  with  a 
constant  temperature  of  freezing  water  ;  with  per- 
petual absence  of  the  stimulus  of  light :  without  mo- 
tion ;  without  change  of  chemical  conditions— with 
almost  absolute  changelessness  for  ages,  why  should 
organisms  change  ?  They  are  now  suited  to  the  en- 
vironment ;  they  could  not  change  without  becom- 
ing unsuited  to  the  environment.  The  forms  from 
the  Age  of  Chalk  have  survived  because  a  deeper 
principle  than  that  of  succession  of  faunas  has  been 
dominant.  It  is  the  principle  of  correlation  of  environ- 
ment and  organism.  The  animal  must  be  adapted 
to  its  surroundings.  Nearly  all  the  populations 
which  have  lived  dwelt  on  land  or  in  comparatively 
shallow  water,  where  environment  was  undergoing 
progressive  change  ;  hence  succession  of  faunas.  A 
few  deep  sea  species  have  dwelt  where  change  of 
physical  conditions  is  almost  unknown ;  hence  a 


Lesson  from  a  Lump  of  Chalk.  209 

nearly  changeless  fauna.    Thus  a  piece  of  chalk  re- 
veals a  deep  and  important  principle. 

The  position  of  the  chalk-beds  in  the  series  of  geo-  Cretaceous 
logical  formations  is  nearly  at  the  top  of  the  Cre-  £J^:    d 
taceous  System.     The  System,   besides  the  beds  of  distribu- 
chalk,  contains  strata  of  sand  and  clay.     One  va-  tion- 
riety  of  sand  is  green,  and  in  New  Jersey,  opposite 
Philadelphia,    it  is   dug  extensively  for  fertilizing 
soils,  since  it  is  not  a  purely  silicious  sand,  but  con- 
tains a  large  percentage  of  potash.    The  Cretaceous 
strata  extend  along  the  belt  parallel  to  the  Atlantic 
and  Gulf  coasts,  into  Mexico  ;  but  from  Maryland  to 
Georgia,  the  Atlantic  belt  is  mostly  covered  and  con-  Eastern 
cealed  by  the  Tertiary  beds.    From  middle  Georgia, 
a  broad  belt  extends  into  eastern  Mississippi,  and  ties. 
thence  north  to  the  Ohio  River  near  Cairo.    West  of 
this,  the  Cretaceous  strata  are  concealed  by  Tertiary 
and  Mississippi   alluvium,  as   far  as   Little   Rock. 
Near  here   an   exposed   belt   begins  which  widens 
extensively  toward  the  southwest,  through   Texas. 
Remember  that  the  place  of  the  Tertiary  strata  is 
always  between  the  Cretaceous  and  the  ocean.    The 
Cretaceous  strata  go  down  under  the  Tertiary,  and 
probably  under  the  Gulf  and  a  portion  of  the  At- 
lantic. 

There  is  no  proper  chalk  in  the  Cretaceous  beds  of 
the  United  States.  In  the  Gulf  States,  however,  is  a 
buffish  soft  limestone,  called  the  "  Rotten  Lime- 
stone," slightly  resembling  chalk.  As  it  disinte- 
grates and  mingles  with  vegetable  matter,  it  forms  a 
very  rich,  black  soil.  This  underlies  the  very  best 
cotton  lands  of  Georgia,  Alabama,  and  eastern  Mis- 
sissippi. The  lower  part  of  the  System  contains  beds 


210      Walks  and  Talks  in  the  Geological  Field. 

of  sand  interstratified  with  clays  and  shales.  These 
convey  rain  water  down  and  southward  from  their 
belts  of  outcrop.  So  when  holes  are  bored  from  the 
surface  down  to  these  water-bearing  sands,  supplies 
of  water  are  obtained.  Hence  it  is,  that  at  Selma, 
Cahaba,  and  throughout  the  Cretaceous  region,  Ar- 
tesian wells  abound. 

Fossils.  The  Cretaceous  rocks  of  the  Gulf  States  are  rich  in 
fossil  remains  ;  often,  in  riding  along  the  highway, 
one's  eye  is  arrested  by  some  weathered  knoll  close  by 
the  roadside,  thickly  overstrewn  with  teeth  and  verte- 
brae of  sharks  and  rays  of  various  extinct  species — as 
if  one  were  traveling  over  a  sea-bottom.  Here  also, 
are  multitudes  of  small  and  curious  oyster  shells,  and 
many  other  sorts  of  shells.  Where  the  rivers  and 
creeks  have  cut  through  the  Cretaceous  strata  we  find 
excellent  sections.  One  of  the  most  famous  of  these 
is  at  Prairie  Bluff,  on  the  Black  Warrior  River,  in 
Greene  County,  Alabama.  Here  the  "rotten  lime- 
stone "  is  at  the  top  ;  then  come  beds  of  sand  formed 
evidently,  not  far  from  the  ancient  shore,  which  lay 
on  the  north,  just  beyond  Selma  and  a  little  south  of 
Tuscaloosa.  These  sands  contain  bits  of  wood,  and, 
in  one  instance,  I  remember  seeing  the  trunk  of  a 
tree  projecting  several  feet  from  the  cliff  toward  the 
river.  The  wood  contained  a  good  amount  of  iron 
pyrites,  but  some  of  it  could  still  be  cut  with  a  knife. 
Here  is  one  layer  of  cemented  sand  completely 

Oysters  packed  with  small  oysters.  In  other  strata  I  have 
picked  up  oyster  shells  seven  inches  in  diameter,  and 
nearly  round.  Single  valves,  I  think  weigh  some- 
times two  or  three  pounds.  The  Cretaceous  strata 
seem  to  have  been  a  literal  oyster  cemetery. 


Lesson  from  a  Lump  of  Chalk.  211 

We  do  not  find  any  bones  of  horses  or  oxen,  or  any 
of  our  domestic  and  useful  animals.  Nor  do  we  find 
remains  of  any  of  our  fruit-bearing  trees — or  berries 
of  any  kind.  Instead  of  relics  of  domestic  animals, 
we  discover  teeth  and  vertebrae  of  sharks  of  different 
tribes— some  with  tapering,  lance-like  teeth,  some 
very  long  and  slender,  and  some  flat  and  lying  like 
paving  stones  on  the  bottom  of  the  mouth.  Here 
too  are  the  vertebrae  of  a  long  and  snake-like  reptile  Mosasaur 
known  as  Mosasaur.  It  was  probably  a  genuine 
"sea-serpent."  The  relics  of  these  ancient  popula- 
tions are  now  plowed  up  in  the  cotton  fields.  In  the 
region  south  of  Selma  I  have  seen  the  precious  relics 
of  curious  and  extraordinary  shells,  which  we  call 
JZudistes,  carted  together  and  burned  for  lime  to  Rudistes. 
whitewash  log-cabins. 

From  Texas,  the  great  Cretaceous  belt  can  be  traced 

Western 
northward  to  Kansas,  Nebraska,  Minnesota,  Dakota,  localities. 

and  British  America.  It  extends,  indeed,  along  the 
east  flanks  of  the  Rocky  Mountains,  apparently  to 
the  Arctic  Ocean.  These  are  interesting  facts.  They 
demonstrate  that  there  was  a  time  when  an  ocean 
stretched  from  the  Gulf  of  Mexico,  through  the  mid- 
dle of  our  continent,  to  the  Arctic.  These  Cretaceous 
strata  contain  neither  chalk  nor  "  rotten  limestone." 
They  were  not  formed  in  a  deep  sea.  There  are  vast 
formations  of  clay  and  shale,  and  at  the  bottom  is  a 
thick  sandstone,  often  conglomeritic,  which  can  be 
traced  from  Kansas  to  the  Wahsatch  Mountains— 
but  not  in  one  continuous  sheet.  All  these  Cretaceous 
strata  being  formed  of  fragments  coarse  or  fine,  are 
called  fragmental.  Evidently  they  were  laid  down 
in  waters  mostly  shallow,  and  to  a  great  extent,  near 


Lesson  from  a  Lump  of  Chalk. 


the  shore.  The  western  Cretaceous  beds  contain 
many  strata  of  coal;  and  this  is  other  evidence  of 
water  so  shallow  as  to  become  frequently  dry  land. 
The  fine  coals  of  Wyoming  and  of  the  Cascade  Moun- 
tains in  Washington  are  Cretaceous. 

These  strata  are  the  burial  places  of  gigantic  rep-  Reptiles, 
tiles — dwellers  in  the  sea  and  dwellers  on  the  land. 
Some  of  their  forms  were  amazingly  elongate.    Some 
attained  a  length  of  fifty  to  one  hundred  feet.     I 
must  give  you  the  name  of  one  of  these — Ca-mar"-o- 
sau'-rus.     The  bones  were  found  by  Cope  in   Col-  Camaro- 
orado.    He  says  :    "  One  of  the  vertebrae  of  the  neck  *a 
was  twenty  inches  long  and  twelve  inches  in  trans- 
verse diameter.    The  shoulder-blade  was  5J  feet  long, 
and  the  thigh-bone  five.     The  total  length  of  the 
reptile  must  have  been  72  feet."     Am-phi-ccel'-i-as  Amphi- 
had  a  thigh  bone  six  feet  in  length  and  a  body  over  ca 
a  hundred  feet  long.     Marsh  has  discovered,  also, 
enormous  reptilian  bones  in  Kansas,  and  some  of 
them  are  remarkably  peculiar.    I  can  not  enter  into 
details  at  this  place  ;  but  by  and  by  we  will  take  a 
general  view  of  the  wonderful  empire  of  reptiles. 

Another  system,  the  Jurassic,  underlies  the  Greta-  The 

ceous,  and  we  find  its  shales  and  limestones  widely  Jurassic 

System. 

distributed  in  the  far  west.  It  was  a  closed  record  be- 
fore the  activities  of  Cretaceous  life  began.  It  in- 
closes the  memorials  of  huge  and  numerous  Dino- 
saurian  reptiles,  and  it  was  in  fact  from  these  reposi- 
tories that  Marsh  derived  the  material  to  give  inter- 
est and  romance  to  his  reptilian  memoirs.  Lower 
still  lie  the  sandstones  of  the  Triassic,  and  these  are  Triassio 
the  solid  tombs  of  the  hoar  forerunners  of  the  swarm- 
ing  dynasty  of  reptiles.  The  Triassic  is  represented 


214     Walks  and  Talks  in  the  Geological  Field. 

in  the  eastern  states  by  the  red  and  brown  sandstones 
of  North  Carolina,  northern  New  Jersey  and  the  val- 
ley of  the  Connecticut.  From  the  quarries  along  the 
Connecticut  are  obtained  the  materials  for  the  fine 
brownstone  fronts  of  New  York.  But  these  stones 
are  rich  in  interest  for  the  geologist  as  well  as  the 
builder.  They  contain  the  records  of  a  daily  life 
which  opens  vistas  into  a  wonderful  past  where 
Nature  is  seen  in  one  of  her  stages  of  transition  from 
type  to  type.  We  glimpse  the  stalking  forms  of 
bird-like  reptiles  as  we  uncover  the  tracks  which  they 
made  in  the  world's  middle  ages. 


XXX.     LONE  BURIALS  IN  THE  COAL  LANDS. 

COAL-MEASURE    FOSSILS. 

The  Car-  STILL  deeper  in  the  series  of  strata  which  compose 
boniferous  tne  upper  portion  of  the  earth's  crust,  we  come  to  the 
coal-beds  which  were  described  in  Talk  XXVI.  We 
wish  now  to  consider  very  briefly  the  organic  forms 
which  the  coal  strata  inclose.  We  refer  here  to  coal 
strata  of  "Carboniferous  Age,"  such  as  found  in  the 
United  States  east  of  the  Rocky  Mountains— except- 
ing the  Richmond  and  Deep  River  fields  in  Virginia 
and  North  Carolina.  You  will  remember  that  we  de- 
tected evidences  of  the  vegetable  origin  of  the  coal. 
The  forests  We  conclude  that  it  was  formed  from  trees  and  her- 
of  time,  baceous  plants  which  had  grown  in  the  places  where 
the  coal  accumulated.  Generally,  that  ancient  vege- 
tation has  become  broken,  comminuted,  and  decayed 
— like  the  forest  leaves  gathered  in  a  pile  and  left  to 
the  influence  of  the  weather  during  one  or  two  sea- 


Lone  Burials  in  the  Coal  Lands.  215 

sons.  Still,  many  distinct  traces  of  the  coal-plants 
lie  bedded  in  the  formless  rubbish  of  the  ancient 
forest.  Pressed  upon  the  black  surfaces  of  the  shales 
are  innumerable  traceries  of  fern  fronds,  as  neatly 
preserved  as  if  gathered  last  week  from  the  forest 
and  pressed  by  careful  hands  for  the  herbarium. 

Here  too,  are  imbedded  stems  covered  all  over  with  Lepido- 
seal-like  impressions  arranged  in  diagonally  winding  dendron" 
series.    Such  a  tree  was  Lep-i-do-den'-dron,  or  "  scaly 
tree,"  which  grew  to  a  height  of  a  hundred  feet  with 
a  stem  twelve  feet  in  circumference.    Some  of  the 
smaller  samples  of  these  stems  or  branches  bear  a  re- 
mote resemblance  to  the  exterior  of  a  snake  ;  and  I 
have  had  specimens  brought  as  petrified  snakes  ! 

We  find  also  another  kind  of  stems,  with  similar 

Sigillaria. 

seal-like  impressions,  but  arranged  in  lines  lengthwise 
of  the  stem  and  more  remote  from  each  other.  This 
kind  of  tree  is  Sig-il-la'-vi-a  or  "seal-tree."  Quite 
often  we  find  the  stump  and  roots  of  these  trees 
deeper  down  in  the  sandy  clay  in  which  the  tree 
originally  grew.  These  are  marked  by  scattered, 
deep  impressions,  as  if  made  by  a  sharp  stick.  Be- 
fore these  were  known  to  be  the  roots  of  Sigillaria, 
they  were  named  /Stig-ma'-ri-a  or  "  mark-tree." 

These  trees  were  not  like  any  species  now  living.  These 
They  produced  no  flowers  or  fruits  which  could  be  were  corn- 
compared  with  those  of  modern  vegetation.     Yet  we 
must  admit  that  they  possessed  resemblances  to  sev- 
eral different  kinds  of  modern  vegetation.    When  we 
get  a  fossil  organism  of  this  kind,  we  say  it  is  "  com- 
prehensive."   Thus,  Lepidodendron  had  some  struc- 
tures which  affiliated  it  with  our  modern  "ground 
pine"  (Lycopodium).     In  another  particular  it  was 


216     Walks  and  Talks  in  the  Geological  Field. 


Animals 
of  these 
forests : 
Snails, 


like  the  Cycads  of  tropical  regions.  In  some  charac- 
ters of  the  wood  it  was  a  fir  or  pine,  while  in  others 
it  was  a  fern.  The  " scars''  referred  to  were  left  by 
the  fallen  fronds  or  leaves,  and  in  these  it  also  re- 
sembled ferns.  We  base  these  inferences  on  the  study 
of  specimens  imbedded  in  the  strata  associated  with 
the  coal.  All  comprehensive  types  are  primitive  and 
low  in  rank.  The  low  rank  of  these  plants  is  evinced 
also  by  the  absence  of  flowers  and  fruit. 

But  we  find  here,  also,  the  relics  of  once  animated 
forms.  As  the  coal  was  produced  on  the  land  ;  as  the 
vegetation  grew  on  the  land,  the  animal  remains 
would  be  those  of  the  land.  They  would  be  air- 
breathers.  So  here  they  are— Snails— air-breathing 
mollusks.  Every  one  has  noticed  the  snail  crawling 
about  with  his  house  on  his  back.  He  lives  in  damp 
retired  places,  and  feeds  on  the  leaves  of  herbs.  The 
situation  must  have  been  sufficiently  retired  ten  mil- 
lion years  ago  in  a  forest  where  the  woodman's  axe 
never  resounded,  and  footstep  neither  of  man  nor 
beast  was  ever  heard.  We  find  two  types  of  land- 
snails  in  the  Coal  Measures ;  one  is  like  our  modern 
genus  Helix,  and  the  other  resembles  Pupa. 

I  just  now  intimated  that  these  humble  air-breath- 
ers were  not  disturbed  in  their  retreats  by  man 
or  beast.  This  is  simply  a  conclusion  from  the 
phibians.  fossil  remains.  These  are  the  most  important  records 
of  the  past.  We  have  got  down  to  a  geological 
horizon  or  level  which  answers  to  a  time  when  the 
higher  organisms  had  not  appeared.  So  we  see  that 
they  have  not  enjoyed  an  eternal  existence  on  the 
earth.  But  we  do  find  bones  of  vertebrates— back- 
bones, skulls,  limbs,  and  teeth.  It  is  doubtful 


Verte- 
brates— 
both  fishes 
and  Am- 


Lone  Burials  in  the  Coal  Lands.  217 

whether  they  belonged  to  vertebrates  as  high  even  as 
reptiles.  The  bones  here  seem  to  be  those  of  Am- 
phibians and  Fishes.  Amphibians,  perhaps  you  Whatare 
understand,  are  reptile-shaped  animals  which  breathe  Amphib- 
water  when  young  and  air  when  adult.  Frogs  and  ians? 
toads  are  living  Amphibians  without  tail.  Salaman- 
ders, tritons,  axolotls,  and  fish-lizards  are  Amphib- 
ians with  tails.  But  fish-lizards  retain  their  gills 
throughout  life.  The  gills  are  beautifully  fringed, 
scarlet,  external  appendages,  projecting  from  the  neck 
on  each  side.  We  call  them  Amphibians  because 
in  their  structure  they  so  much  resemble  salaman- 
ders. Moreover,  the  axolotl,  while  in  the  elevated 
regions  of  Colorado  it  retains  its  gills  permanently, 
in  less  elevated  regions,  absorbs  them  and  becomes  a 
salamander.  So  it  happens  that  the  permanence  or 
absorption  of  the  gills  is  not  a  circumstance  of  very 
great  importance. 

The  eggs  of  Amphibians  are  deposited  and  hatched 
in  water,  and  the  young  must,  therefore,  be  fitted 
with  gills.  All  vertebrates  below  Amphibians  have 
gills  for  a  permanency ;  all  above,  have  lungs  for  a 
permanency.  The  Amphibian  is  on  the  dividing  line. 
In  the  lowest  phase  of  its  existence,  it  goes  with 
fishes;  in  the  highest  phase  it  goes  with  reptiles. 
Its  life  is  double.  But,  on  the  one  hand,  the  sepa- 
rating line  leaves  the  fish-lizard  wholly  on  the 
aquatic  side  ;  and  so,  on  the  other  it  leaves  the  toad, 
in  some  cases,  wholly  on  the  land  side ;  since  toads 
sometimes  rear  their  young  without  finding  their 
way  to  the  water. 

These  amphibious  border-land  creatures  possess 
very  great  interest ;  and  so  this  type  of  creatures 


218      Walks  and  Talks  in  the  Geological  Meld. 

fossilized  in  the  Coal  Measures,  throws  much  light  on 
the  problem  of  life  and  organization.  They  are  bor- 
der-land creatures  here  in  an  additional  sense.  Con- 
tiguous to  them  in  earlier  time,  lived  only  water- 
breathing  fishes  ;  next  following  them  in  time,  were 
the  air-breathing  reptiles.  Here  you  notice  a  certain 
succession  in  geological  history  which  is  reproduced 
in  the  life-time  of  the  individual  Amphibian.  Why 
this  parallelism  ?  What  causes  it  ? 

Some  Car-  Let  us  look  a  little  more  closely  at  some  of  these 
boniferous  Coal  Measure  Amphibians.  At  Linton,  Ohio,  and 
ians.  Morris,  Illinois,  and  at  the  Joggins  in  Nova  Scotia, 
we  find  their  blackened  bones  in  greatest  abundance. 
There  is  one  type  in  which  the  animal  was  but  a  few 
inches  long  and  had  the  shape  and  aspect  of  a  sala- 
mander—that is,  with  a  long  tail  and  four  limbs. 
Another  type  was  similar,  but  was  covered  with 
scales  or  small  bony  plates.  Still  another  had  no 
limbs,  or  at  most  only  two,  and  the  form  was  long 
and  snake-like.  All  this  is  ascertained  from  the  ruins 
of  skeletons  found  in  the  Coal  Measure  shales. 
Labyrinth-  ^e  most  characteristic  and  striking  of  all  Coal 
odonf.  Measure  types  of  animals  was  the  Lab-y-rinW-o-dont. 
In  size,  some  were  as  large  as  an  ox,  and  larger.  The 
head  of  one  species  was  three  feet  long  and  nearly 
two  feet  broad.  The  teeth  of  Labyrinthodonts,  like 
those  of  all  Amphibians,  were  conical,  but  on  mak- 
ing a  cross  section,  the  cement  and  dentine — the  two 
substances  of  which  the  tooth  is  composed,  are  found 
intricately  infolded  in  a  labyrinthine  fashion,  and 
hence  the  name  of  this  type.  In  some  of  the  Laby- 
rinthodonts, the  figure  was  somewhat  frog-like,  with 
hind  limbs  much  the  largest.  Whether  they  prac- 


Lone  Burials  in  the  Coal  Lands.  219 

ticed  leaping  we  do  not  know.  That  they  sometimes 
walked  as  quadrupeds  is  certain,  for  in  some  in- 
stances, their  footprints  have  been  preserved  on  the 
surface  of  sandstones.  They  were  found,  for  in- 
stance, near  Greensburg,  Pennsylvania,  and  also  in 
other  American  localities.  The  print  of  the  hind  foot 
is  four-toed,  with  a  thumb  standing  out  at  right 
angles ;  and  the  appearance  is  so  much  like  that 
of  the  human  hand,  that  when  the  animal  was  only 
known  from  its  foot-prints,  it  was  named  Cheir-o-the'- 
ri-um  or  "  hand-beast."  In  some  Labyrinthodonts 
the  head  and  some  other  parts  of  the  body  were 
covered  with  sculptured  bony  plates. 

Numerous   remains    of  smaller   Amphibians   are  Thesto 
found  in  Nova  Scotia,  in  company  with  numerous  told  by  a 
snail  shells,  in  the  stump  of  an  old  SigUlaria.    In  the  stumP- 
same  situation  were  found,  also,  galley-worms,  scor- 
pions, and  spiders.    These,  undoubtedly,  all  served 
as  food  for  the  Amphibians.    Nearly  all  the  forms  of 
insect  life  are  represented  among  the  relics  of  the  coal 
epoch — myriapods  of  various  groups,  scorpions  and 
spiders,  cockroaches,  dragon-flies  and  other  netted 
winged  insects,  and  also  a  few  beetles.    But  we  find 
no  remains  of  the  highest  insects— flies,  butterflies, 
ants,  wasps,  and  bees.    Many  insect  forms  discovered 
are    aquatic,  and   undoubtedly  served  as  food    for 
fishes  and  Amphibians. 

If  we  examine  the  limestones  associated  with  other  The  life 
strata  in  the  Coal  Measures,  especially  from  Ohio  forms 
westward,  we  find  them  stocked  with  a  rich  and 
varied  fauna  of  marine  remains.    Besides  numerous  lime- 
tribes  and  genera  of  sharks  and  ganoid  fishes,  these  st( 
limestones  abound  in  corals,    crinoids    and  various 


220      Walks  and  Talks  in  the  Geological  Field. 

families  of  univalve  and  bivalve  mollusks.  Oysters, 
however,  are  almost  or  totally  wanting  ;  and  no  fish 
remains  resembling  the  modern  perch  and  whitefish 
occur.  There  is  a  strikingly  antique  aspect  to  these 
relics.  The  affinities  are  with  the  old  forms  which 
we  shall  next  discover,  and  not  with  the  forms  of  the 
modern  world.  We  have  here  penetrated  to  the  rec- 
ords of  the  Palaeozoic  JEon. 


XXXI.     TERRIBLE  FISHES   AND  THEIR  COM- 
PANIONS. 

REMAINS  OF  THE   DEVONIAN   AGE. 

WE  now  descend  another  stage  in  our  examination 
of  the  strata  and  their  contents.  We  come  down  to 
the  Devonian  System.  Do  not  think  these  rocks  are 
everywhere  covered  by  all  the  later  ones.  In  many 
regions  they  come  to  the  surface  because  none  of  the 
later  ones  are  there  present.  But  where  the  Devo- 
nian strata  disappear  they  go  under  the  Carboniferous 
strata ;  and  these  go  under  all  the  newer  strata  which 
may  be  present.  Remember,  however,  as  before  said, 
that  a  whole  formation  may  be  found  missing  in  par- 
ticular places.  Strata  were  deposited  only  where  sea- 
bottom  existed.  If  the  spot  was  uplifted  so  as  to  be 
dry  land  during  a  particular  age,  the  formation  be- 
longing to  that  place  can  not  exist.  But  if  the  spot 
became  sea-bottom  in  the  next  age,  the  formation  be- 
longing there  was  deposited,  and  it  does  not  now  lie 
on  the  formation  of  next  preceding  age,  but  on  the 
one  before  that. 


Terrible  Fishes  and  their  Companions.       221 

So  do  not  imagine  ourselves  penetrating  deeper  and 
deeper  into  the  earth.  We  examine  the  systems  of 
strata  in  the  regions  where  they  come  to  the  surface. 
We  may  presume  they  continue  under  the  newer  for- 
mations to  great  depths ;  but  I  have  the  opinion 
that  if  we  could  follow  them,  they  would  be  fofund 
gradually  growing  thinner. 

Let  us  begin  by  learning  where  the  Devonian  strata 
occupy  the  surface.  Nowhere  in  New  England  are  of  Ameri- 
they  distinctly  revealed.  Nor  in  any  of  the  Gulf  ^ni^T 
States.  A  belt  of  Devonian  strata  stretches  east  and  rocks, 
west  through  central  and  southern  New  York,  from 
the  Helderberg  Mountains  to  Lake  Erie.  Thence  it 
passes  under  Lake  Erie  and  along  both  shores  to 
the  extremity  of  the  lake,  and  into  southeastern 
Michigan.  Here  the  outcrop  divides  ;  one  branch 
passes  south,  through  the  west  center  of  Ohio  to  the 
Ohio  River,  and  the  other,  turning  north,  goes  under 
Lake  Huron  and  along  its  western  border  to  the 
Straits  of  Mackinac.  This  branch  here  bends  west- 
ward and  south  west  ward,  so  as  to  underlie  the  cen- 
tral and  eastern  part  of  Lake  Michigan,  and  border 
that  lake  on  the  east.  This  branch  goes  down 
through  Indiana  to  the  Ohio  River,  at  the  Falls  of 
the  Ohio,  lying  along  the  eastern  border  of  the  great 
Coal  Field  of  Indiana,  Illinois,  and  Kentucky.  A 
belt  also  extends  from  Rock  Island,  Illinois,  north- 
westward by  Iowa  City,  through  the  state  of  Iowa. 
This  system  is  found  also  in  Missouri,  Kentucky, 
Tennessee,  and  other  states. 

There  is  a  very  useful  key  to  the  distribution  of  the 
rocks  of  any  system.  There  is  always  a  great  lime- 
stone formation  from  the  middle  to  the  upper  part 


222     Walks  and  Talks  in  the  Geological  Field. 


Lime- 
stone for- 
mations 
in  various 
rock  sys- 
tems. 


The  De- 
vonian 
Limestone 
—or  Cor- 
niferous. 


Fossil 
corals : 


Acervu- 
laria. 


of  the  system  —  not  always  extending  to  the  top  of  it 
—and  this  is  generally  quite  conspicuous,  in  conse- 
quence of  its  solidity  and  prominence  and  great  use- 
fulness. The  great  central  limestone  mass  of  a  sys- 
tem may  be  traced  through  all  the  windings  of  its 
outcrop,  by  a  line  of  quarries  and  cliffs  and  rocky 
ridges.  If  you  can  say  where  this  conspicuous  central 
limestone  belt  is  located,  you  can  at  once  understand 
that  the  older  strata  of  the  system  must  lie  on  the 
side  from  which  the  limestone  dips,  and  the  newer 
strata  must  lie  on  the  side  toward  which  the  lime- 
stone dips.  Now,  the  great  limestone  mass  of  the 
Devonian  is  the  Corniferous  Limestone.  Throughout 
the  west,  the  overlying  Hamilton  formation  is  also 
a  limestone,  though  mostly  shaly  at  the  east.  The 
limestone  mass,  therefore,  from  Ohio  westward,  is 
Corniferous-Hamilton.  .Some  of  the  points  where 
the  Devonian  limestone  mass  rises  conspicuously  are 
the  following  :  Syracuse,  Leroy,  Caledonia,  Buffalo, 
Ingersoll,  London,  Sandusky,  Kelly's  Island,  Colum- 
bus, Monroe,  Alpena,  Mackinac,  Petoskey,  Rock 
Island,  Iowa  City,  Louisville.  At  all  these  points  we 
find  a  limestone  of  nearly  the  same  age,  containing 
generally  an  abundance  of  marine  fossils.  The  cor- 
als are  very  conspicuous,  and  at  the  Falls  of  the  Ohio, 
and  the  head  of  Little  Traverse  Bay,  appear  to  have 
been  gathered  together  in  literal  reefs. 

At  Petoskey  and  vicinity  occur  those  exquisite 
coral  masses  which  are  so  extensively  polished  and 
sold  to  summer  tourists.  The  masses  range  from  the 
size  of  a  hickory  nut  to  that  of  a  man's  head  ;  but 
the  most  common  are  of  the  size  of  the  fist.  They 
are  shaped  somewhat  like  cakes  made  in  "patty 


Terrible  Fishes  and  their  Companions.        223 

pans."  The  upper  surface  is  covered  with  six-sided 
cells  about  a  quarter  of  an  inch  in  diameter.  A  deli- 
cately crenulated  wall  runs  around  each  cell.  In  the 
middle  of  the  cell  appears  to  be  a  small  cylindrical 
wall  running  down  along  the  length  of  the  coral 
tube.  Within  this  sinks  a  pit  abruptly  an  eighth  of 
an  inch.  Really,  however,  there  is  no  true  inner 
wall.  From  this  apparent  wall  regular  radial  lines 
run  to  the  outer  wall.  These  are  the  upper  edges  of 
vertical  radiating  plates  called  septa,  which  extend 
the  whole  length  of  the  coral  tube.  These  forms  are 
beautiful  enough  without  polishing.  Still,  certain 
internal  structures  are  by  polishing,  brought  out  with 
admirable  clearness  and  beauty.  For  instance,  if  the 
cake  is  split  vertically  and  one  surface  polished,  you 
see  that  the  space  between  each  two  septa  is  divided 
from  end  to  end  by  delicate  horizontal  dissepiments, 
giving  the  whole  polished  surface  the  appearance  of 
a  piece  of  very  fine  woven  cloth.  The  dealers  in 
these  specimens  give  them  various  names,  some  of 
which  are  quite  absurd.  The  scientific  name  of  this 
species  is  A-cer-wu-la'-ri-a  Da-vid-sof-ni.  The  first 
word  signifies  a  little  hillock  or  cake ;  the  second, 
means  Davidson's ;  and  we  might  call  it  "  Davidson's 
coral-cake. ' '  This  Davidson  was  a  very  distinguished 
English  writer  on  fossil  Brachiopods. 

This  species  is  found  in  America  nowhere  except  in 
the  Hamilton  Group,  which  you  will  remember, 
runs  into  the  Corniferous  Limestone.  It  is  found 
nowhere  in  the  world  in  such  beauty  and  abundance 
as  on  the  south  shore  of  Little  Traverse  Bay.  The 
perfect  specimens  occur  imbedded  in  soft  blue  clay 
forming  beds  ten  or  twelve  inches  thick  between 


224      Walks  and  Talks  in  the  Geological  field. 

sheets  of  solid  limestone.  One  can  extract  them 
with  the  naked  hand.  By  Drift  action  these  coral 
cakes  have  been  transported  like  bowlders,  from  the 
northern  part  of  the  state  all  over  the  southern  part. 
The  same  coral  is  found  also  near  Iowa  City  and 
sparingly  at  other  localities. 

Favosites.  There  is  another  fine  coral  found  on  the  shore  of 
Little  Traverse  Bay,  which  has  been  named  Fav-o- 
si'-tes  Al-pe-nen'-sis,  which  means  the  "AlpenaFav- 
osite."  Alpena  is  at  the  head  of  Thunder  Bay  on  the 
east  shore  of  the  state,  and  this  coral  occurs  very 
abundantly,  also,  in  that  region.  It  is  shaped  like  a 
potato,  roundish  or  oblong,  and  is  covered  all  over 
with  small  cell-mouths  which  are  nearly  circular  in 
outline,  but  often  angular,  from  mutual  crowding. 
When  one  of  these  coral  potatoes  is  split  open,  and 
one  surface  polished,  the  tubes  which  run  down  from 
the  surface  can  be  beautifully  seen— as  also  the  trans- 
verse divisions  or  tabulce,  and  the  perforations  or 
pores  along  the  outer  walls  of  the  tubes. 

Small  It is  quite  wonderful  to  see  the  number  of  parasitic 

parasitic    creatures  which  attached  themselves  to  these  and 

shells  and 

corals.  other  corals.  The  surface  of  Acervulana  was  some- 
times a  whole  world.  Here  is  a  little  bivalve  shell 
spreading  its  fibrous  rootlets  out  to  make  itself  secure 
(Crania).  Here  are  numerous  little  coiled  shells 
(Ser'pula)  of  the  class  of  Worms.  Here  is  a  little 
coral  consisting  of  a  branching  chain  of  cornet- 
shaped  tubelets  attached  with  the  small  end  of  each 
to  the  under  side  of  its  predecessor,  near  the  up- 
turned aperture  (Au-lop'-o-ra).  There  are  half  a 
dozen  species  of  these.  One  aggregated  itself  in 
dense,  thick  masses.  One  was  beautifully  small  and 


Terrible  Fishes  and  their  Companions.        225 

delicate.  One  was  extremely  fine,  almost  like  a 
spider's  web  trailing  over  the  surface— really  a  distinct 
genus.  Then  we  find  patches  an  inch  in  diameter 
and  less,  which  look  like  films  of  varnish  pricked 
full  of  pin-holes  at  equal  distances.  There  are  coarser 
and  finer  sorts  (Fis-tu-lip'-o-ra  and  Cal-lop'-o-ra). 
Another  incrusting  coral  is  like  excessively  fine  lace 
(Mon-tic-wrlip'-o-ra).  At  Thunder  Bay,  on  Par- 
tridge Point,  is  an  amazing  quantity  of  delicate  coral 
structures  composed  mostly  of  little  bars,  slightly 
divergent,  lying  in  one  plane,  and  having  cross-con- 
nections, forming  a  structure  in  some  cases  like 
woven  cloth,  with  open  meshes.  One  finds  an  amaz- 
ing number  of  variations  in  details.  I  have  picked 
out  from  this  locality  alone  one  hundred  different 
species  of  these  (Fe-nes-tel'-li-dce)  and  related  forms 
(all  Bry-o-zo'-ans).  Then,  at  Widder  in  Ontario,  we  Bivalve 
find  a  regular  bank  of  bivalve  shells  of  a  certain  shells- 
species  (Spi-rif'-e-ra  mu-cro-na'-ta]  called  "  petrified  n' 
butterflies  "  by  the  boys  of  the  vicinity.  The  deposit 
has  been  cut  through  by  the  Great  Western  Railway. 
The  Hamilton  strata  are  almost  everywhere  well 
stocked  with  the  treasures  of  the  ancient  sea ;  and  I 
have  observed  that  the  small  and  parasitic  species  are 
more  abundant  than  in  other  formations.  The 
greater  part  of  the  good  fossils  found  in  the  Drift  of 
the  northwestern  states  are  derived  from  this  group. 

But  after  all,  the  most  astonishing  relics  of  the  Fishes. 
Devonian  Age  are  the  fish-plates  and  fish-teeth  found 
in  the  upper  part  of  the  System.    Some  years  ago,  a  Dinich- 
German-American  clergyman  came  to  me  with  fine     ys' 
specimens  of  fossils  from  Ohio,  among  which  were 
teeth  and  jaws  of  fishes,  which  he  had  laboriously 


226      Walks  and  Talks  in  the  Geological  Field. 

worked  out  of  concretions  found  in  the  vicinity  of 
Delaware,  Ohio.  The  concretions  were  imbedded  in 
shales  immediately  above  the  Hamilton  formation. 
This  was  Rev.  Hermann  Hertzer  ;  and  he  urged  with 
much  persistence  that  I  undertake  the  description 
of  the  fossils.  Knowing,  however,  that  Dr.  J.  S. 
Newberry  was  at  work  on  fossil  fishes,  I  finally  in- 
duced him  to  turn  his  fish-remains  over  to  Dr.  New- 
berry  ;  and  they  now  constitute  a  part  of  the  palseon- 
tological  collection  of  Columbia  College.  Dr.  New- 
berry's  description  of  these  and  other  Ohio  fishes  may 
be  found  in  the  first  volume  of  the  Report  on  the 
Palaeontology  of  Ohio.  The  two  principal  genera 
have  been  named  Din-ich'-thys  (terrible  fish)  and 
As-pid4ch'-thys  (shield-fish). 

The  cranium  of  Dinichthys  was  composed  of  thick 
bony  plates,  strengthened  with  massive  internal 
arches,  and  was  at  least  two  feet  in  length  and  the 
same  in  breadth.  The  jaws  have  on  their  margins, 
near  the  middle,  a  number  of  conical  teeth  soldered 
to  the  bone— not  inserted  in  sockets — and  at  the  front 
of  each  jaw,  two  strong,  curved,  triangular  teeth, 
interlocking  together.  These  teeth  are  shaped  from 
the  solid  bony  tips  of  the  jaws.  The  bpdy  was  pro- 
tected by  bony  plates  which  on  the  back  were  large 
and  thick.  The  body  must  have  been  about  three 
feet  in  diameter,  and  its  length  from  fifteen  to  twenty 
feet.  Other  fish  remains  of  the  same  age,  named 
A  'dich-  ^spidtehthy8  belonged  also  to  a  bony  plated  fish  as 
thys.  large  as  Dinichthys ;  but  its  plates,  as  far  as  known, 

are  covered  with  large,  hemispherical,  smooth,  en- 
ameled tubercles. 
In  the  Corniferous  Limestone  we  find  also  quite 


Ancestry  of  the  Pearly  Nautilus.  227 

numerous  bones  and  teeth  of  fishes.  They  all  belong, 
however,  to  those  orders  which  include  the  modern 
Sharks  and  Gar-Pikes  or  Ganoids.  No  trace  of  soft- 
scaled  fishes  is  certainly  known  below  the  Mesozoic. 
Some  of  these  sharks  had  enormous  bayonet-like 
spines  inserted  in  front  of  certain  of  their  fins ;  and 
the  Ganoids  were  armed  with  strong,  conical  teeth, 
and  protected  by  bony  enameled  scales. 

Every  one  has   read  or  heard  of  the  "Old  Red  The  Old 
Sandstone."    In  some  parts  of  this  Scottish  forma-  RedSand- 
tion  were  found  fish  remains  which  Miller,  a  quarry- 
man,  described  years  ago,  in  a  popular  and  fascina- 
ting style  which  attracted  much  attention.    This  was 
one  of  the  earliest  attempts  to  interest  the  public  in 
fossil   remains— and    we   might   even   add,  in  any 
branch  of  geology.    The  renowned  fishes  of  Scotland 
were  mostly  Placoderms,  like  Diniehthys.    But  no 
European  fishes  possess  any  greater  interest  than  our 


XXXII.      ANCESTRY  OF  THE  PEARLY   NAU- 
TILUS. 

SILURIAN  REMAINS. 

THE  Pearly  Nautilus  still  lives  in  the  deep  waters 
of  tropical  seas. 

Our  Pearly  Nautilus  is  no  sailor.    He  can  indeed  The 
float  with  all  his  tentacles  outspread,  but  his  normal  Pearly 
place  is  on  the  bottom  of  the  sea,  and  his  normal  gait  represents 
is  a  sprawling  crawl  on  a  set  of  flexible,  slippery  an  old 
tentacles,  with  mouth  to  the  ground  and  back  up. 

This  Nautilus  is  the  representative  of  a  venerable 


228      Walks  and  Talks  in  the  Geological  Meld. 

dynasty.  The  type  is  a  survival  from  remote  Palaeo- 
zoic times.  It  perpetuates  a  plan  of  structure  so  an- 
cient that  its  Chambered  Shell  lies  imbedded  with  its 
contemporaries  in  strata  of  Carboniferous,  Devonian, 
Silurian,  and  Cambrian  age.  We  have  turned  over 
their  remains  in  searching  for  the  relics  of  those 
ages ;  but  we  have  reserved  to  this  time  the  men- 
tion of  this  diversified  type.  But  let  us  first  glance 
at  the  rocks  which  we  are  to  explore. 

Rocks  of  We  shall  call  them  Silurian.  Very  commonly  they 
e  siiu-  are  ^nown  as  Upper  Silurian.  They  lie  many  thou- 

and  their   sand  feet  down  from  the  surface,  in  regions  where  the 

distri-        series  of  strata  is  complete.     But  in  other  regions, 
button. 

they  rise  up  to  sunlight  and  atmosphere,  with  all 

their  treasures  of  the  ancient  world  embosomed  in 
their  solid  mass.  Here,  also,  is  a  great  limestone 
formation— the  Niagara  Limestone.  We  find  it  at 
the  Niagara  River,  which  gives  its  name.  It  is  seen 
along  the  gorge  from  Lewiston  to  the  Falls.  It  is 
the  top  rock  of  this  gorge,  and  over  its  brink  at 
the  Falls,  the  vast  body  of  water  is  precipitated. 
The  reaction  of  the  water  against  the  underlying 
shale  wears  it  away.  The  limestone  is  undermined, 
and  huge  pieces  break  off  from  time  to  time.  So  the 
Falls  recede  ;  so  the  gorge  is  continued  backward  ;  so 
the  seven-mile  gorge  was  formed ;  and  we  have  re- 
cently ascertained  that  during  thirty-three  years  the 
recession  has  been  three  feet  a  year. 

From  the  Falls  eastward,  this  limestone  continues 
its  outcrop  to  Rochester  and  beyond.  Westward  and 
northwestward  it  trends  toward  Cape  Hurd,  a  prom- 
ontory separating  Georgian  Bay  from  Lake  Huron. 
Continuing  under  the  northern  part  of  Lake  Huron, 


Ancestry  of  the  Pearly  Nautilus.  229 

it  forms  the  southern  portions  of  the  Mauitoulin 
Islands  ;  it  borders  the  northern  shore  of  Lake  Mich- 
igan ;  separates  Bay  de  Noc  and  Green  Bay  from 
Lake  Michigan,  and  borders  the  western  side  of  the 
lake  to  Chicago,  extending  beyond  and  into  north- 
western Indiana.  From  northwestern  Illinois,  a 
belt  stretches  northwestward  diagonally  across  Iowa. 
At  Sandusky,  Ohio,  an  area  expands  like  a  great 
spatula  over  parts  of  Ohio,  Indiana,  and  Kentucky, 
stretching  to  the  southern  part  of  Kentucky.  But 
through  the  broadest  part  of  this  spatula  is  a  great 
oval  perforation,  within  which  are  embraced  Cincin- 
nati, Richmond  (Ind.),  Madison,  Frankfort,  and 
Lexington  (Ky.).  On  the  great  Silurian  mass  of 
limestone  are  situated  Rochester,  Niagara  Falls,  Mil- 
waukee, Chicago,  Joliet,  Huntington  (Ind.),  San- 
dusky.  Next  below  the  Niagara  Limestone  lies  the 
Niagara  Shale,  and  then  the  Clinton  formation  ;  but 
both  of  these  become  limestones  at  the  west,  and 
unite  with  the  Niagara  limestone  to  augment  the 
central  mass.  Next  above  the  Niagara  limestone 
comes  the  Salina  formation,  of  shales,  clays,  and 
marly  limestones — a  formation  which,  as  we  stated  in 
Talk  XXIII.,  yields  the  country  a  vast  amount  of  salt 
and  gypsum.  At  the  bottom  of  the  Silurian  are 
found  two  fragmental  formations,  the  Oneida  Con- 
glomerate and  the  Medina  Sandstone  above  it — pro- 
claiming intelligibly  that  the  waters  were  disturbed 
when  the  Conglomerate  was  deposited,  more  quiet  «cycleof 
when  the  materials  of  the  sandstone  were  laid  sedimen- 
down,  and  still  quieter  when  the  fine  sediments 
settled  down  which  formed  the  Clinton  marls  and 
the  Niagara  shale.  Please  bear  in  mind  thi&  law 


230      Walks  and  Talks  in  the  Geological  Meld. 


Silurian 
fossils : 


Cham- 
bered 
shells. 


Orthoce- 
ras. 


of  the  succession  of  different  kinds  of  sediments. 

Now  let  us  examine  the  contents  of  these  Silurian 
strata.  In  the  lowest  beds — the  Oneida  Conglom- 
erate—nothing of  much  importance  has  been  found. 
This  does  not  surprise  us,  for  shells  and  corals  must 
have  been  ground  to  powder,  had  they  been  mingled 
with  the  rolling  stones  of  which  that  formation  is 
composed.  The  Medina  sandstone  was  fine  enough 
to  allow  the  accumulation  of  some  organic  remains. 
We  find  small  heaps  of  petrified  seaweeds.  One  sort 
is  regularly  jointed,  and  presents  a  somewhat  elegant 
appearance  (Ar-throphf-y-cus).  We  are  much  inter- 
ested to  be  able  to  discover  which  way  the  currents 
set  over  the  soft  sand.  In  New  York  it  is  common  to 
find  a  sandstone  surface  with  a  little  shell  lying,  con- 
vex side  up,  and  beyond  it  a  train  or  drift  of  sand 
a  few  inches  long,  and  diminishing  to  a  point.  How 
similar  were  the  conditions  of  the  sandy  beach  then 
and  now  !  How  surprising  that  a  little  ridge  of  soft 
sand  formed  millions  of  years  ago,  should  have  been 
so  carefully  preserved  through  all  the  storms  and 
revolutions  of  the  world  to  our  day  ! 

It  is  in  the  limestones,  and  especially  the  Niagara 
Limestone,  that  we  find  the  relics  of  the  ancestors 
of  the  Pearly  Nautilus.  It  may  seem  strange  that 
most  of  them  are  straight  rather  than  coiled.  But 
their  structures  are  the  same,  and  the  coiling  is  a 
circumstance.  These  straight  nautiloid  shells  we  call 
Or-tho-cer'-a-tites  (the  technical  name  of  the  genus 
being  Or-thoc'-e^ras  or  "  straight  horn  ").  Like  Nau- 
tilus, the  shell  is  divided  by  cross  partitions  or  septa 
at  frequent  intervals.  Like  Nautilus,  it  is  a  grad- 
ually tapering  tube.  Like  Nautilus,  there  is  near  the 


Ancestry  of  the  Pearly  Nautilus.  231 

center  of  each  septum,  a  small  perforation  from 
which  leads  a  little  tube  to  the  next  septum,  and 
thus  through  all  the  septa  and  intervening  chambers. 
This  tube  is  the  siphuncle.  Like  Nautilus,  each  sep- 
tum is  simply  and  plainly  concave  with  the  con- 
cavity turned  toward  the  larger  end  of  the  shell.  As 
in  Nautilus,  the  last  chamber  is  deep,  and  undoubt- 
edly this  was  the  portion  to  which  the  animal  was 
confined.  If  Nautilus  should  be  uncoiled,  it  would 
be  precisely  an  Orthoceras.  We  can  think  back  the 
wide-tentacled  bodies  which  rested  in  the  outer 
chamber.  We  can  see  them,  in  thought,  spreading 
their  strong  arms,  glaring  with  their  great  glassy 
eyes,  pursuing  with  hungry  ferocity  their  prey,  tear- 
ing with  their  lance-like  mandibles,  and  feeding  with 
the  gusto  and  relish  of  a  true  carnivore. 

We  notice  among  the  dead  chambered  shells  some 
variations.  In  form,  a  few  are  slightly  bent,  while 
most  are  straight.  In  some,  the  traverse  section  is 
oval,  while  generally,  it  is  almost  circular.  In  some, 
the  place  of  the  siphuncle,  instead  of  being  central, 
is  a  little  distance  away  from  the  center— but  not  in 
the  margin.  We  notice,  also,  that  the  septum  is 
sometimes  undulate  around  the  margin,  instead  of 
plane.  Thus  nature  shows  a  susceptibility  to  vary. 
Her  forms  are  fashioned  after  fundamental  plans,  but 
not  all  cast  in  one  mould.  For  some  reason  which 
may  be  inscrutable,  she  seems  always  playing  off 
from  the  main  path,  with  a  sense  of  freedom  rather 
than  necessity. 

Right  here,  in  the  midst  of  these  ancient  Orthocer- 
atites,  are  the  relics  of  organisms  decidedly  divergent. 
Here  are  coiled  chambered  shells  which  almost  any 


232      Walks  and  Talks  in  the  Geological  Field. 

person  would  identify  with  Nautilus.  They  really 
have  all  the  essential  characters  of  Nautilus  ;  but  you 
will  notice  that  they  are  not  closely  coiled  ;  we  do  not 
find  each  whorl  overlapping  and  concealing  all  the 
others  ;  and  the  last  whorl  is  even  a  little  separated 

Lituites.  from  the  preceding  one  (Lit-wA'-tes).  Many  others 
are  coiled,  but  somewhat  loosely,  and  the  siphuncle 
is  one  side  of  the  center— sometimes  close  to  the  outer 

Gyroceras.  margin  (Qy-voc'-e-ras).  Still  others  are  curved 
enough  to  form  one  whorl,  but  not  properly  coiled, 

Cyrtoceras. an^  the  siphuncle  is  close  to  the  outer  margin  (Cyr- 
toc'-e-ras).  But  we  have  not  time  to  trace  all  the 
varieties  of  the  type  of  chambered  shells  even  among 
the  Silurian  limestones. 

In  strolling  through  the  quarries  excavated  in  the 
Niagara  limestone— in  the  suburbs  of  Chicago,  for  in- 
stance, or  at  Joliet  or  Waukesha — our  attention  is 
constantly  arrested  by  the  remains  of  shells,  corals, 

Brachio-     an^  crinoids.    The  bivalve  shells  are  chiefly  Brach'- 

pods.  i-o-pods.1  They  are  lower  in  rank  than  clams  and 
river  mussels.  They  may  always  be  known  by  hav- 
ing the  beak  and  hinge  in  the  center  of  the  valve, 
with  the  valves  presenting  the  same  slope  and  curva- 
ture each  way  from  the  beak.  They  may  also  be 
known  by  having  one  valve  more  swollen  than  the 
other.  Many  also,  have  a  deep  depression  (Sinus) 
along  one  valve  from  the  beak  to  the  opposite  mar- 
gin, and  a  corresponding  elevation  (Fold)  in  the  op- 
posite valve.  Brachiopods  are  now  nearly  extinct. 

Gastero-     ^ne   univalve     shells    are    mostly    Gas'-ter-o-pods. 

pods.          These  are  higher  in  rank  than  clams  and  mussels. 

i  Many  zoologists  regard  the  Brachiopods  as  worms — not  mol- 
lusks.  F.  S. 


Ancestry  of  the  Pearly  Nautilus. 


The  Crinoids  were  plant-like  forms  (Zo'-o-phytes)  _. 
but  strictly  animals  in  nature.  The  most  common 
kinds  were  rooted  to  the  muddy  sea-bottom.  The 
old  roots  are  found  going  down  into  the  clay  like  the 
roots  of  an  oak.  Above  the  root  rises  a  stony  stem, 
ten  or  fifteen  inches  high,  and  from  an  eighth  to 
half  an  inch  in  diameter.  This  is  simply  a  pile  of 
little  button-like  discs,  each  one  with  a  hole  through 
the  center,  and  some  radial  striae  on  the  flat  sides. 
So  there  is  a  perforation  through  the  whole  length  of 
the  stem.  Sometimes  several  of  the  segments  remain 
attached  together;  but  generally  they  are  separated 
and  scattered  through  the  rock.  In  some  European 
countries  they  have  long  been  known  as  "  St.  Cuth- 
bert's  beads."  We  find  them  in  great  abundance  in 
the  Drift  of  the  northwestern  states.  At  the  top  of 
the  stem  we  find  a  little  urn  composed  of  many 
stony  plates  nicely  joined  together  by  their  edges. 
The  urn  has  a  cover  similarly  formed.  Most  of 
these  bodies  are  found  disjointed  in  the  rocks ;  but 
there  is  one  which  seems  to  have  held  together  very 
firmly  (Car-y-oc'-ri-nus)  and  is  found  in  the  Niagara 
strata  almost  everywhere.  The  external  surfaces  of  ri 
the  plates  of  the  cup  are  elaborately  chased  and  em- 
bossed ;  but  this  I  must  tell  you  is  not  an  armed 
and  rooted  crinoid  ;  it  is  a  Cystid,  having  no  arms 
and  with  a  tail-like  stem.  In  the  true  crinoids  we 
find  a  row  of  arms— generally  ten — rising  from  the 
border  of  the  urn  or  cup  ;  and  these  often  branch  or 
give  off  a  delicate  fringe.  The  arm  and  its  subdivi- 
sions are  composed  of  flattened  stony  plates  or  pieces 
joined  together  according  to  the  general  plan  of  the 
animal. 


234      Walks  and  Talks  in  the  Geological  field. 

We  thus  see  that  when  nature  adopts  a  particular 
method  for  the  construction  of  one  part  of  an  animal, 
she  pursues  faithfully  the  same  method  in  the  for- 
mation of  all  the  parts.  Thus  it  appears  that  the 
works  of  nature  are  formed  according  to  plans.  Any- 
thing which  is  a  plan  has  been  thought  out.  The 
plans  of  nature  are  the  expressions  of  mind. 


XXXIII.     THE  KING   CRAB'S  GRANDFATHER 
AND  OTHER  GRANDFATHERS. 

CAMBRIAN  FOSSILS. 

ONE  who  strolls  along  the  coast  of  New  England 
The  King  Or  the  contiguous  islands  will  notice  many  things 
"  cast  up  by  the  sea,"  but  one  of  the  most  interesting 
is  the  King  Crab,  Lim'^u-lm  Pol-y-phe-mus.  It  seems 
to  be  essentially  a  wide  basin  with  a  small  and  spike- 
like  handle.  It  is  in  fact  employed  by  the  fisherman 
for  removing  water  from  his  boat.  The  same  objects 
are  strewn  along  the  beach  all  the  way  to  Charleston. 
A  few  years  ago,  Professor  A.  8.  Packard  determined 
to  make  the  acquaintance  of  the  King  Crab's  family 
and  study  his  pedigree.  He  studied  the  King  Crab's 
its  em-  eggs-  He  studied  them  seriously  and  thoroughly  by 
bryology,  the  aid  of  microscopes.  More  strictly  speaking,  he 
studied  the  progressive  development  of  the  embryo 
within  the  egg.  He  believed — for  many  others  so 
believe — that  the  several  embryonic  stages  are  pic- 
tures of  the  ancestors  of  the  animal.  He  believed 
that  the  first  trace  of  an  embryonic  form  would  be  a 
picture  of  the  remotest  ancestor — either  in  its  embry- 
onic or  adult  stage  ;  and  that  the  phases  presented  by 


The  King  Craft's  Grandfather.  235 

the  later  stages  of  the  embryo  would  be  pictures  of 
later  ancestors. 

Professor  Packard  discovered  that  the  earlier  em-  in(jividu- 
bryo  of  the  King  Crab  shows  a  striking  resemblance  to  ai  embry- 
the  early  stages  of  soft-shelled  shrimps  and  low  fresh  *^ts  ^ce 
water  crustaceans  now  living ;  and  that  in  a  later  history, 
stage,  the  embryo  of  the  King  Crab  was  strikingly 
like  certain  Tril'obites  found  fossil  in  the  Cambrian 
strata.    There  are  at  least  three  genera  of  such  Tril- 
obites — Ag-nos'-tus  and  Sa'-o  from  the  bottom  of  the 
Cambrian,  and  Tri-nu'-cl&us  from  the  Upper  Cam- 
brian.    Now,  the  meaning  of  this  is,  according  to 
some,  that  our  King  Crab  is  descended  from  the  same 
primeval  stock  as  these  Trilobites ;  and  that  all  the 
Trilobites  were  descended  from  that  stock.    This,  in 
fact,  means  evolution,  and  that  all  the  Crustacea  have 
descended  from  the  same  primitive  stock. 

But  what  are  Crustaceans  ?  Aquatic  animals  cov-  Crustacea, 
ered  by  a  crust  which  is  composed  of  a  series  of  seg- 
ments or  rings  joined  by  their  edges  ;  and  having 
more  than  eight  feet.  Of  these,  Lobsters  and  Craw- 
fishes are  examples.  And  what  are  those  Trilobites  ? 
They  are  crustaceans  in  which  the  body  is  divided 
lengthwise  by  two  grooves,  into  three  lobes— the  axis 
running  along  the  middle,  and  a  lateral  lobe  each 
side.  The  Trilobites  were  very  ancient  animals.  I  Trilobites. 
say  "were,"  because  the  last  of  them  perished  mil- 
lions of  years  ago,  during  the  progress  of  the  Carbon- 
iferous Age.  Here  are  the  tombs  of  their  remotest 
ancestors.  Here  lie  their  forms  imbedded  in  these 
primordial  sandstones  and  slates. 

Let  me  explain  about  these  sandstones  and  slates. 
At  Potsdam,  in  northern  New  York,  and  throughout 


236     Walks  and  Talks  in  the  Geological  Meld. 


Potsdam    ^at  vicmity>  a  grav  sandstone  lies  at  the  surface- 

Sandstone,  the  same  as  referred  to  in  Talk  XIX.  It  stretches 
across  the  St.  Lawrence  River,  and  northeastward 
along  its  valley.  It  encircles  the  Adirondack  high- 
lands. This  is  the  Potsdam  Sandstone.  Westward 
it  stretches  through  Canada  to  the  Sault  Ste.  Marie, 
and  along  the  south  shore  of  Lake  Superior  to  Ke- 
weenaw  Point.  The  "  Pictured  Rocks  "  are  part  of  it. 
Southward  from  this  shore  it  disappears  under  the 
Trenton  Limestone.  It  is  the  Potsdam  Sandstone 

its  fossils,  which  forms  the  lower  portion  of  the  high  cliffs 
along  the  Upper  Mississippi  River.  It  is  in  this 
sandstone  that  multitudes  of  these  ancestral  Tril- 

_  ..  .  obites  lie  packed  away.  They  have  had  a  hard  time 
however.  They  are  all  in  pieces,  and  it  is  difficult  to 
get  sufficient  pieces  together  to  describe  any  one  of 
the  species.  The  sands  from  which  this  sandstone 
was  formed  must  have  beaten  to  and  fro  in  shallow 
water,  or  along  some  beach  for  many  years.  These 
Trilobites  are  but  a  few  inches  in  length. 

Besides  Trilobites,  we  find  in  the  Potsdam  Sand- 
stone, many  remains  of  little  bivalve  shells  called 

lAn  ula  Lin'gula.  This  is  a  genus"  of  Brachiopods.  The  name 
signifies  a  "little  tongue,"  referring  to  the  shape. 
This  is  a  remarkable  genus,  for  it  has  been  in  exist- 
ence on  the  earth  from  the  epoch  of  the  Potsdam 
Sandstone  to  the  present.  In  every  formation  are 
some  species  of  Lingula;  and  living  species  may  be 
found  along  our  Atlantic  coast,  clinging  by  their 
fleshy  peduncles  to  the  wharves  and  other  supports. 
Another  remarkable  fact  about  Lingula  is  this  :  Its 
shell  is  composed  largely  of  bony  substance  —  phos- 
phate of  lime  —  while  the  shells  of  ordinary  mollusks 


The  King  CraVs  Grandfather.  237 

are  composed  of  stony  substance — carbonate  of  lime  ; 
and  this  peculiarity  of  constitution  has  clung  to  this 
little  type  through  all  the  ages. 

It  is  a  peculiarity  of  Brachiopods  to  have  the  two  symmetry 
valves  unequal ;  one  is  more  convex  than  the  other.  and  non- 
The  more  convex  valve  has  also  the  more  projecting  in  bivalve 
beak.  But  each  is  symmetrical  taken  by  itself.  shells- 
That  is,  if  you  lay  it  down  on  the  side,  you  see  the 
beak  in  the  middle,  and  on  each  side  of  it,  the  out- 
line of  the  valve  presents  the  same  shape  and  curve. 
Now,  the  clam  and  river  mussel  are  quite  different. 
In  these,  the  two  valves  are  equally  convex  ;  and,  if 
you  consider  one  valve  by  itself,  it  is  not  symmetri- 
cal. That  is,  if  you  lay  a  valve  down  on  its  side,  you 
find  the  beak  nearer  one  end ;  and  the  slope  of  the 
shell-outline  is  not  the  same  on  each  side  of  the  beak. 
Shells  of  this  sort  belong  to  the  class  La-mel'-li- 
branchs.  All  the  difference  in  the  forms  of  these  two 
classes  arises  from  the  position  of  the  animal  in  the 
shell.  In  the  Lamellibranchs,  one  valve  is  on  the 
right  side  and  the  other  on  the  left.  So  the  principle 
of  bilateral  symmetry  makes  one  valve  the  counter- 
part of  the  other.  In  the  Brachiopods,  one  valve  is 
on  the  back  and  the  other  over  the  abdomen.  So 
the  principle  of  bilateral  symmetry  does  not  operate 
between  the  two  valves  ;  but  the  right  and  left  sides 
of  each  valve  separately  are  symmetrically  developed. 
By  bilateral  symmetry  we  mean  the  law  or  principle 
which  causes  every  feature  of  the  right  side  of  an 
animal  to  have  a  corresponding  feature  on  the  left 
side.  This  principle  runs  through  the  whole  animal 
kingdom.  Even  among  the  starfishes,  crinoids, 
corals,  or  other  so-called  "radiate"  animals,  we  can 


238      Walks  and  Talks  in  the  Geological  Meld. 

draw  a  line  which  will  separate  right  and  left  sides. 
Try  it  in  a  starfish. 

Other  The  Potsdam  Sandstone  from  northern  New  York 

am  nan  ^Q  ]yjinnesota  appears  to  be   the   lowest  formation 
above  the  Eozoic  crystalline  rocks.    The  copper-bear- 
ing rocks  are  older,  but  it  is  not  yet  decided  whether 
we  should  regard  them  as  embraced  in  the  Palaeo- 
zoic System  or  not.    There  is  also,  in  Wisconsin  and 
Minnesota,    a   massive   quartzite   formation   under- 
neath the  Potsdam  Sandstone  ;  but  as  it  is  not  fully 
their          proved  to  contain   any  fossils,  we  are  not  certain 
fossils.       whether  to  call  it  Eozoic  or  not.    But  in  Vermont,  in 
eastern  Massachusetts,  and  in  New  Brunswick  are 
slates  which  underlie  the  Potsdam  and  contain  fos- 
sils.   ("Acadian"  or  "St.  John  "  Group.)    Some  of 
these  were  Trilobites  ten  to  twenty  inches  long. 
Cambrian      Down  in  these  lowest  Palaeozoic  strata  we  find  also, 
life  varied  other  remains  of  animal  types.    Here,  for  instance, 
and  well     are  „  chambered  shells  "—the  grandfathers  of  those 

a  eve  loped. 

described  in  the  last  Talk.  We  find  here  Or-thocf- 
e-ras,  as  well  as  some  marked  deviations  from  it. 
Here  are  the  oldest  examples  known  of  this  type. 
Here,  we  might  say,  was  its  first  introduction  to  the 
world;  and  we  might  begin  to  query  how  it  came 
here.  We  should  be  inclined  to  think  it  was  an 
abrupt  introduction,  without  predecessors,  gradually 
more  and  more  simple  as  we  should  trace  them  into 
remote  ages.  If  an  abrupt  introduction,  it  was  not 
an  evolution  from  some  older  form,  because  evolution 
proceeds  by  gradual  transitions.  Such  is  the  conclu- 
sion of  some  scientific  men ;  and  if  we  were  obliged 
to  form  a  conclusion  on  the  whole  question  from  the 
facts  connected  with  the  first  appearance  of  cham- 


The  King  CraVs  Grandfather.  239 

bered  shells,  I  think  we  should  all  say  they  did  not 
appear  according  to  the  method  of  evolution.  We 
must  be  candid,  however,  and  consider  all  the  cir- 
cumstances. We  only  wish  to  ascertain  how  the 
facts  were — not  to  make  ourselves  think  them  differ- 
ent from  the  reality.  Now  we  know  full  well  that  Does  it 

the  rocks  older  than  the  Cambrian  have  been  sub-  dl8P«>ye 

evolution? 
jected  to  such  actions  since  they  were  deposited  as 

ocean-sediments,  that  their  aspect  is  totally  trans- 
formed. We  may  feel  confident  that  if  any  shells  or 
corals  had  been  originally  inclosed  in  the  sediments, 
they  would  have  been  destroyed.  Especially  would 
carbonate  of  lime  have  disappeared.  Therefore,  we 
are  not  certain  that  no  chambered  shells  existed  be- 
fore the  Cambrian.  They  may  have  existed.  They 
may  have  been  so  formed  and  constituted  as  to  show 
that  the  Cambrian  species  were  not  suddenly  intro- 
duced, but  made  their  appearance  in  such  graduated 
succession  as  evolution  implies.  Here,  at  least,  is  a 
possibility  which  prevents  us  from  feeling  confident 
that  the  Cambrian  Orthocer'atites  were  introduced  by 
a  sudden  creation. 

In  these  lowest  Cambrian  strata  are,  also,  still  other  Cambrian 
forms.    Here  we  find  Gas'-ter-o-pods— univalve  shells  llfe  types, 
coiled  up.    These,  too,  are  well  advanced  from  any 
humble  beginning  of  Gasteropods — in  case  they  be-  Gastero- 
gan  in  a  humble  way.    The  same  queries  arise  as  in  P°ds» 
the  case  of  chambered  shells.    Now,  to  recapitulate, 
we  find  in  these  lowest,  fossil-bearing  strata,  remains 
of  several  types  of  animals  appearing  to  our  knowl-  Crustacea, 
edge  for  the  first  time,  but  all  well  advanced  beyond 
the  lowest  grades  of  the  orders  to  which  they  belong. 
Here,  in  the  very  lowest  strata,  are  Trilobites ;  Lin- 


240     Walks  and  Talks  in  the  Geological  Field. 

Brachio-    9ula  an<^  some  related  genera  of  Brachiopods,  as  well 
pods,  etc.    as    Or' -this,  quite  a  different    genus,  and   perhaps 
Worms.    At  the  very  dawn  of  the  Cambrian  Age 
numerous  types  well  advanced  in  rank,  suddenly  ap- 
peared.   You  will  notice,  however,  that  several  im- 
portant types  of  animals  were  absent.    Here  were  no 
corals,  no  crinoids,  no  Bryozoans,  no  Lamellibranchs. 
Rocks  of        So  far  we  have  confined  our  attention  to  the  lowest 
upper        group  of  the  Cambrian  rocks,  composed  of  the  Aca- 
and  lowest  dian  or  St.  John  formation  and  the  Potsdam  Sand- 
Silurian.    stones.    Next  above  the  Potsdam  is  the  Calciferous 
formation.    It  is  very  conspicuous  along  the  bluffs  of 
the  Upper  Mississippi,  where  it  forms  generally  the 
Calciferous  upper  half.    Like  the  Potsdam  Sandstone  it  is  huffish 

formation  in  colo     and  Disposed  to  crumble  to  pieces.    In  the 

or  Lower 

Magnesian  northwest   it    is   known  as  the  Lower    Magnesian 

Lime-        Limestone.    It  contains  the  lead  mines  of  Missouri 

stone. 

(Talk  XXI.).    Above  this  comes  the  St.  Peters  Sand- 
st.  Peters   stone,  white,  clean,  and  destitute  of  fossils ;  but  this 

sandstone.  is  not  known  at  the  east.       Next  is  the  Trenton 

Trenton 

Lime-         Group,  which  contains  the  great  Trenton  Limestone. 

stone.  Like  the  other  great  central  limestone  masses  (Niag- 
ara, Corniferous,  Lower  Carboniferous)  this  forms  a 
conspicuous  landmark  across  the  country,  and  con- 
stitutes the  rich  repository  of  the  remains  of  the 
animals  which  dwelt  in  the  Upper  Cambrian  ocean. 
This  limestone  mass  forms  the  bluffs  at  St.  Paul  and 
Minneapolis ;  comes  up  on  the  north  side  of  the 
Manitoulin  Islands ;  stretches  westward  across  Ste. 
Mary's  River,  and  running  through  the  Upper 
Peninsula  of  Michigan,  goes  down  along  the  west 
side  of  Green  Bay,  into  southern  Wisconsin,  north- 
ern Illinois,  and  northeastern  Iowa,  holding  the  lead 


Earth's  Deepest  Graves.  241 

mines  in  these  three  states ;  outcrops  over  a  large 
area  about  Cincinnati,  extending  to  Madison  and 
Richmond,  Indiana,  and  Frankfort  and  Lexing- 
ton, Kentucky  ;  outcrdps  again  at  Nashville  and  sur- 
rounding region ;  stretches  through  central  New 
York  to  Watertown,  and  across  the  St.  Lawrence  to 
Georgian  Bay,  stretching  along  its  eastern  shore  and 
emerging  again  at  the  Manitoulin  Islands.  Every- 
where, this  group  of  limestones  and  shaly  limestones 
is  wonderfully  rich  in  the  remains  of  creatures  which 
swarmed  in  the  seas  of  the  twilight  ages  of  the 
world. 


XXXIV.     EARTH'S  DEEPEST  GRAVES. 

THE    EOZOIC    ANIMAL,. 

WE  are  down  now,  on  the  bottom  rocks  of  the 
earth's  crust.  This  is  the  home  of  the  vitrified  and 
crystalline  bowlders  which  overstrew  the  surface. 
There  are  fifty  thousand  feet  of  later  strata  resting 
above  these  rocks  in  regions  where  the  series  is  com- 
plete. But  here,  and  over  extensive  regions,  the  deep 
Eozoic  beds  have  been  arched  up  to  the  surface,  and 
no  newer  rocks  have  ever  formed  over  them ;  or  if 
they  were,  have  subsequently  been  worn  away.  Let 
us  see  what  has  been  found  out. 

In  the  first  place,  deep  as  we  have  ever  penetrated  Eozoic 
into  these  Eozoic  rocks,  they  all  retain  some  traces  rocks  were 
of  stratification.    In  most  cases,  the  stratification  is  iments. 
very  obscure ;  in  many  cases,  it  is  quite  obliterated, 
but  rocks  of  this  sort  furnish  some  evidence  of  their 
original  bedding.    Sometimes  we  can  trace  them  into 


242      Walks  and  Talks  in  the  Geological  Field. 

continuity  with  stratified  rocks.  In  all  cases  the 
crystals  which  they  contain,  and  the  crystalline  con- 
dition of  the  rocks  indicate  solidification  from  a  state 
of  solution  or  softening  which  requires  the  presence 
of  water.  Grant  us  water  and  heat,  and  the  present 
condition  would  be  produced  from  ordinary  ocean 
sediments.  We  must  look  upon  all  these  rocks  as 
ocean-born.1  Hard  and  crystalline  as  they  now  are, 
we  must  think  of  them  as  at  one  time  in  the  condi- 
tion of  ocean-slime.  These  rocky  beds  have  been  suc- 
cessively ocean-bottom.  These  rocks  too,  have  suc- 
cessively rested  as  sediments  upon  an  ocean-bottom 
preexisting.  There  must  have  been  an  ocean-bottom 
for  the  very  first  sediments  to  rest  on.  Let  us  remem- 
ber this. 

Kindsof  In  tne  next  place,  the  very  oldest  rocks  known  are 
rocks.  granites,  syenites,  gneisses,  and  hornblendic  schists. 
Not  having  seen  the  bottom  of  this  series,  we  cannot 
state  its  thickness.  At  a  higher  level,  have-  been 
found,  in  the  northwest,  conglomerates,  quartzites, 
and  marble,  all  together  attaining  a  thickness  of  one 
thousand  to  six  thousand  feet.  Then  come  various 
schistose  rocks  and  diorites  ;  and  about  here  occur 
great  beds  of  haematite  or  iron  ore.  This  series  is  four 
thousand  or  five  thousand  feet  thick.  Next  above  are 
black  slates  and  schists,  often  ferruginous,  and  other 
diorites,  making  about  twenty-six  hundred  feet  more. 
Next,  are  five  thousand  feet  of  mica  schists,  and 
finally,  several  hundred  feet  of  granite  and  gneiss 
and  kindred  rocks.  These  rocks  altogether  aggregate 
a  thickness  not  exceeding  twenty-five  thousand 

i  The  rocks  here  called  Eozoic  are  now  a  subject  of  much 
study,  and  re-classification  of  many  appears  necessary  and  new 
views  are  arising  as  to  their  origin.  F.  S. 


Earth's  Deepest  Graves.  243 

feet.  But  this  may  not  embrace  all.  In  Canada,  Sir 
William  Logan  computed  the  Eozoic  rocks  as  fifty 
thousand  feet  thick,  and  that  estimate  is  generally 
adopted.  The  thing  of  chief  importance  here,  is  to 
know  that  the  thickness  is  great,  and  the  rocks  are 
all  crystalline. 
Now,  we  explore  these  old  rocks  from  bottom  to  Whyfos- 

top,  and  scarcely  find  a  trace  of  organic  remains.  S1^sare 

absent 
Who  could  expect  fossil  shells  or  corals  imbedded  in  or  rare. 

hard  rocks  consisting  of  fragments  of  crystals  and 
grains  of  quartz,  feldspar,  mica,  and  hornblende? 
The  nature  of  the  rock  proclaims  changes  in  consti- 
tution which  must  have  dissolved  or  destroyed  all 
relics  of  the  hard  parts  of  animals.  Here  must  be 
some  lost  chapters  of  the  history  of  life — the  first 
chapters  in  the  volume.  It  is  like  the  loss  of  the 
Alexandrian  Library.  Could  the  records  of  those 
earliest  ages  be  restored,  how  many  outstanding 
doubts  and  irresolvable  problems  would  be  disposed 
of!  But  since  the  records  are  wanting  we  must 
proceed — not  as  if  they  never  existed,  but  by  some 
rational  process  to  reproduce  them.  From  the  bot- 
tom of  the  Cambrian  up,  we  have  learned  well  the 
general  tenor  of  the  history  of  life.  We  must  pro- 
ject that  tenor  backward  toward  a  lost  beginning. 

But  thanks  to  the  Canadian  geologists,   the  first  Thedis- 
chapters  are  not  completely  lost.    We  have  a  frag-  covery  of 
ment   of  a   page ;   and  we  know   about   where   in 
the  book  it  belonged.    In  the  lower  part  of  this  vast 
series  of  rocks  are  in  Canada  three  great   beds   of 
marble  or  crystalline  limestone.     In  the  third,  or 
upper  one,  occur  some  forms  which  appear  to  be  or- 
ganic.   These  were  brought  to  the  notice  of  the  sci- 


244     Walks  and  Talks  in  the  Geological  Meld. 

entific  world  in  1856.  They  have  been  studied  by 
mineralogists,  palaeontologists,  and  chemists.  They 
have  been  subjected  to  most  searching  microscopic 
study.  The  general  opinion  is  that  they  are  organic 
remains  ;  and  they  have  by  general  consent  been  re- 
ferred to  a  group  of  organisms  of  low  grade  called 
Fo-ram-i-nif'-e-ra — the  same  as  that  to  which  Glo- 
bigeri'na  belongs  (Talk  X.).  A  few  mineralogists  re- 
gard them  as  inorganic.1  These  forms  have  been 
obtained  at  several  localities  in  Canada,  as  also,  in 
New  York,  near  Troy,  in  Ireland,  in  Bohemia,  and 
elsewhere.  They  contain  certain  features  which,  in 
my  opinion,  could  not  be  regarded  as  of  mineral  or- 
igin. On  the  contrary,  they  closely  resemble  some 
structures  found  in  certain  Foraminifera. 

structure  In  the  mass,  we  notice  a  concentric  or  laminated 
otEozoon.  structure,  as  if  the  organism  were  formed  of  numer- 
ous layers  wrapped,  one  about  another.  These  layers, 
in  most  cases,  consist  alternately  of  serpentine  and 
carbonate  of  lime.  The  serpentine,  as  is  believed, 
occupies  the  place  of  the  fleshy  part  of  the  animal, 
while  the  carbonate  of  lime  is  its  skeleton ;  and  we 
may  speak  of  it  as  coral,  for  in  many  respects  it  was 
like  coral,  though  produced  by  an  animal  much 
lower  in  rank  than  the  polyps  which  secrete  true 
coral.  When  we  prepare  extremely  thin  slices  of 
this  skeleton,  some  minute  structures  are  seen  under 
the  microscope,  which  convince  us  of  their  animal 
nature.  The  name  of  this  creature  is  E-o-zo'-on  can- 
a-den'-se  or  the  "  Dawn  Animal  of  Canada." 
Now,  if  we  understand  correctly  the  nature  of  this 

i  The  number  of  opponents  to  the  organic  nature  of  Eozoon  in- 
creases.   F.  S. 


Earth's  Deepest  Graves.  245 

animal,  it  was  related  to  A-mce'-ba,  a  minute  soft  Natureof 
creature  often  found  in  stagnant  fresh  waters.  Those  Eozoan. 
who  use  the  microscope  to  search  for  animalcules 
may  sometimes  discover  in  the  field  of  view,  a  little 
shapeless  lump  which  seems  like  a  particle  of  dirt,  ex- 
cept that  it  is  partially  transparent.  While  wishing 
it  out  of  the  way,  it  is  seen  to  move.  On  one  side  is 
extended  a  little  arm  or  tentacle  ;  this  is  then  with- 
drawn. But  suddenly  one  or  two  others  are  pro- 
truded ;  and  we  find  that  the  creature  generally 
keeps  two  or  three  tentacles  extended.  But  one 
or  all  may  be  very  capriciously  withdrawn  ;  and 
when  withdrawn,  it  is  impossible  to  trace  any  out- 
line of  them.  The  tentacles  melt  into  the  general 
substance  of  the  body.  In  the  interior  can  be  seen 
what  is  called  a  "  nucleus  "  and  a  "  contractile  ves- 
icle." 

Attending  carefully  to  the  movements  of  Amoeba, 
we  discover  that  they  have  an  end  in  view.  The  ten- 
tacles are  extended  in  search  of  food.  See  !  its  arm  is 
wound  about  a  minute  animalcule  ;  it  holds  it,  but 
now,  it  does  not  convey  it  to  the  mouth.  Where  is 
the  mouth?  In  truth,  there  is  none.  The  arm  is 
absorbed — animalcule  and  all.  It  disappears  in  the 
common  mass  of  jelly,  and  the  animalcule  is  seen 
within  it.  So  this  creature  feeds.  It  gets  around  its 
food  successfully  ;  but  it  simply  pours  itself  over  it. 
What  an  amazing  simplicity  of  structure  is  here  ! 
Indeed,  there  is  no  structure.  Whenever  the  ani- 
mal takes  breakfast,  it  extemporizes  an  arm  for 
seizing  it.  Whenever  it  eats,  a  mouth  is  extempo- 
rized for  admission  of  food,  and  a  stomach  is  extem- 
porized for  receiving1  and  digesting  it.  From  all  the 


246     Walks  and  Talks  in  the  Geological  Meld. 

ailments  of  hands,  mouth,  teeth,  and  stomach  this 
animal  is  happily  free.  Exempt  from  headache,  sore 
eyes,  ringing  ears,  and  heart-flutterings,  it  still  exer- 
cises all  the  functions  requisite  to  make  it  an  animal. 

And  this  modern  creature  is  the  representative  of 
Eozoon.  But  Eozoon  could  not  be  placed  defenseless 
in  the  sea.  A  little  lump  of  jelly  would  be  swept 
into  annihilation  by  the  force  of  the  waves.  Eozoon, 
however  planted,  held  fast  to  its  support,  and  imme- 
diately secreted  a  strong  roof  over  him  for  protec- 
tion. A  thousand  little  holes  through  the  roof  al- 
lowed threads  of  its  gelatinous  substance  to  be  pro- 
truded. These  coalesced  in  a  common  film  which 
spread  over  the  roof  like  a  coating  of  tar.  This  was 
unprotected,  and  a  second  and  higher  roof  was  built. 
The  structure  was  now  two  stories  high.  Through 
the  upper  roof  innumerable  minute  perforations  al- 
lowed the  jelly  of  the  second  story  to  be  protruded 
in  fine  threads,  and  these  in  turn  coalesced,  and  a 
third  roof  was  secreted.  Thus  the  process  continued, 
and  the  structure  became  many  stories  high.  Mean- 
time other  individuals  were  planted  by  this,  or  near 
this,  and  by  and  by,  they  were  so  enlarged  that  they 
grew  together,  and  grew  as  one  animal.  So  hun- 
dreds and  thousands  of  animals  grew  together  and 
continued  to  grow  and  enlarge  the  structure  during, 
probably  a  thousand  years. 

As  time  passed  on,  this  organism  grew  old  and 
effete.  The  life-time  of  its  species  was  drawing  to  a 
close.  It  was  destined  to  be  replaced  by  something 
better  suited  to  the  improved  circumstances  of  the 
world.  All  the  time,  however,  the  sediments  had 
been  gathering  about  the  bases  of  the  rising  reef- 


An  Earlier  Beginning.  247 

mass.  The  eozoonal  reef-structures  were  buried  and 
forgotten— buried  thousands  of  feet  deep— buried  in 
sea-sediments  which  became  stone.  Then  the  seons 
of  the  world  continued  to  roll  by.  In  the  Age  of 
Mind,  a  marble  edifice  was  demanded  to  meet  some 
want  of  civilization.  The  primeval  tomb  was  opened 
by  the  quarry  man,  and  there  rested  the  relics  of  the 
first  inhabitant  of  our  globe.  It  is  that  of  which  we 
have  been  speaking. 


XXXV.     AN  EARLIER  BEGINNING. 

INTIMATIONS  OF  A   FIERY   ^EON. 

WE  are  searching  for  a  beginning.  We  have  fol- 
lowed down  the  succession  of  formations  to  what 
seems  a  foundation  ;  but  we  perceive  this  must  rest 
on  something  which  already  existed ;  it  can  not  be 
the  beginning.  It  is  an  ocean-born  mass  of  sedi- 
ments. The  ocean  preceded  the  sediments.  Some- 
thing for  the  ocean  to  rest  on  preceded  the  ocean ; 
what  was  that?  Not  something  born  of  ocean. 
What  existed  before  ocean  and  ocean  sediments  ? 

You  have  just  seen  (Talk  XXXIV.)  that  the  deepest  Howsed- 
rocks  are  hard  and  crystalline.    We  have  concluded  iments 
that  their  condition  has  probably  resulted   largely  changed 
from  the  action  of  water  and  heat.     Water  alone  into 

Eozoic 

would  not  dissolve  the  substances  of  which  these 
crystals  are  composed  ;  but  heated  water  would  be 
much  more  efficient.  Moreover,  the  addition  of  al- 
kali to  the  heated  water  would  enable  it  to  dissolve 
nearly  all  the  substances  in  these  lower  rocks.  How- 
ever mud-like  or  sandy  the  sediments  originally  were, 


248     Walks  and  Talks  in  the  Geological  Meld. 

Hot  alka-  neated  alkaline  waters  would  dissolve  them  ;  and 
line  waters  then,  if  the  solution  were  allowed  to  cool,  the  various 
anagent"    constituents  would  enter  into  such  combinations  as 
suited  their  several  affinities  for  each  other.    So  the 
resulting  state  of  the  materials  would  be  extremely 
different  from  that  of  the  original  sediments. 
Source  of       ^u^  *n  ^is  connection,  the  important  point  is  the 
the  heat,    evidence  of  ancient  heat  universally  extended.    I  do 
not  suppose  the  metamorphism  of  the   rocks   has 
taken  place  at  the  surface.    The  heat  engaged  seems 
to  have  been  interior  heat.    It  was  shut  in  and  re- 
tained for  ages  by  overlying  masses  of  strata.    And 
yet  I  doubt  if  all  metamorphic  regions  now  exposed 
have  been  formerly  covered.    Much  yet  remains  to 
be  learned  about  metamorphism. 

The  wast-  That  the  heat  was  internal  is  evinced  by  many 
age  of  heat  proofs  of  the  continued  existence  of  internal  heat, 
cooling  You  will  recall  the  facts  cited  in  Talk  XVII.  You 
earth.  wjn  recall  the  phenomena  of  geysers  and  hot  springs 
(Talk  XIV.).  You  will  remember  that  lavas  from 
volcanoes  come  up  from  some  heated  interior  (Talk 
XV.).  Your  thoughts  will  again  glance  over  the 
thousands  of  square  miles  of  surface  covered  by  lavas 
which  issued  through  fissures  in  the  age  preceding 
the  present  (Talk  XVI.).  You  will  be  vividly  im- 
pressed with  the  conviction  that  intense,  fusing  heat 
exists  within  the  earth ;  and  since  all  heat  tends  to 
waste  away,  you  will  conclude  that  the  earth's  sur- 
face temperature  was  much  higher  some  millions 
of  years  ago  than  it  is  at  present.  The  wastage  of 
the  earth's  heat  is  proved  by  actual  observation. 
Science  has  measured  the  amount  of  heat  which 
comes  to  the  earth  annually— that  is,  the  amount  on 


An  Earlier  Beginning.  249 

each  square  yard— and  has  also  measured  the  amount 
which  escapes  annually ;  and  it  is  thus  shown  that 
the  wastage  exceeds  the  receipts.  The  earth  is  grow- 
ing cold.  This  great  fact  is  established  by  experi- 
ment, by  observation  on  the  escape  of  heat  from 
within,  and  by  the  records  of  an  ancient  higher 
temperature  than  now  exists  at  the  surface. 

Cooling  off!    That  disclosure  puts  our  minds  in  a  Trace 
new  attitude  toward  the  world's  history.   We  have  to  backward 
contemplate  the  earth  as  a  cooling  globe.    That  points  toryof  a 
our  thoughts  ^backward,  along  a  progress  of  cooling.  cooling 
Not  the  slightest  evidence  exists  that  the  laws  of  heat 
are  different  under  our  observation,  from  the  laws 
which  controlled  the  cooling  of  the  ancient  world. 
We  know  what  they  are,  and  what  they  were.    It. 
is  as  safe  to  base  backward  calculations  on  them  as  to 
base  forward  calculations   on  the   planetary  move- 
ments which  bring  conjunctions  and  eclipses. 

This  is  the  way  reasoning  leads  us  : — Following  the  An  ocean- 
course  of  cooling  backward,  we  arrive  at  a  time  such  less  globe; 
that  water  could  not  have  existed  on  the  earth.  All 
the  water  of  the  earth  must  have  been  vapor  or 
gas  suspended  in  the  atmosphere.  At  a  time  when 
no  ocean  had  existed,  no  ocean-sediments  had  been 
deposited,  all  those  rocks  which  have  resulted  from 
marine  sedimentation  were  yet  non-existent.  The 
earth  had  probably  a  solid  surface  of  some  kind  ;  but 
to  emit  heat  sufficient  to  hold  all  the  water  of  the 
world  in  an  uncondensed  state,  the  temperature  of 
the  surface  must  have  been  high— perhaps  a  glowing 
temperature. 

But  even  here  we  are  in  the  midst  of  a  cooling  pro-  A  molten 
cess.    Why  not  ?     Who  can  affirm  that  the  world  be-  world; 


250      Walks  and  Talks  in  the  Geological  Meld. 

gan  to  exist  as  a  red-hot  body  ?  You  know  that  red- 
hot  matter  may  be  made  white-hot ;  and  then  by  in- 
crease of  heat,  may  be  rendered  liquid.  We  must 
trace  this  history  back  to  a  molten  world. 

A  world  Is  there  now  any  ground  for  refusing  to  trace  the 
of  vapor,  history  farther  back?  This  is  a  cooling  process.  There 
is  no  certain  beginning  for  a  cooling  process  except  in 
a  temperature  so  high  that  the  heated  matter  exists 
as  a  mere  vapor,  or  perhaps  gas.  There  is  no  known 
remoter  condition  of  matter,  though  we  may  con- 
ceive the  temperature  indefinitely  high.  It  is,  let  us 
say,  the  remotest  condition  which  we  seek.  Now  all 
terrestrial  substances  are  capable  not  only  of  fusion, 
but  of  volatilization.  Iron  and  the  other  metals  have 
been  reduced  to  vapor.  So,  by  reversing  conditions, 
all  gases  may  be  liquefied  and  then  consolidated. 
Carbonic  acid,  oxygen,  nitrogen,  chlorine,  have  been 
made  solid.  The  form  under  which  matter  exists 
is  a  circumstance  depending  on  temperature  and 
pressure.  There  is  no  inherent  improbability  that  all 
the  matter  of  the  world  was  once  so  heated  as  to 
exist  in  the  form  of  vapor,  or  even  of  gas.  Before 
our  eyes  worlds  are  existing  in  those  states. 

We  should  distinguish  between  vapor  and  gas. 
Gas  is  dry,  like  atmospheric  air — like  steam  in  the 
boiler ;  vapor  is  composed  of  minute  liquid  particles 
floating  in  a  gaseous  medium — like  the  cloud  of  steam 
condensed  in  the  air  after  escaping  from  the  boiler. 
There  may  be  mineral  vapors  as  well  as  igneous 
vapors.  Most  mineral  vapors  must  be  intensely 
Fire-mist,  heated.  We  may  call  such  a  vapor  "fire-mist."  If 
the  earth  were  vaporized  by  heat,  to  what  limits  in 
space  would  the  vapor  extend?  We  must  think  of 


An  Earlier  Beginning.  251 

that.    If  the  earth  was  ever  a  fire-mist  globe  its  di- 
mensions were  vastly  greater  than  at  present. 

There  is  another  thought  to  be  mentioned  here.  Thesoiar 
The  earth  is  only  one  of  a  system  of  worlds,  and  system, 
there  is  good  reason  for  believing  that  any  remote 
origin  which  we  can  establish  for  the  earth  must 
represent  the  remote  origin  of  the  other  planets. 
In  saying  they  are  one  system,  I  refer  to  their 
common  motions  about  one  sun ;  to  the  com- 
mon elliptic  form  of  their  orbits ;  to  the  fact  that 
all  move  from  west  to  east ;  that  all  revolve  nearly 
in  one  plane;  that,  so  far  as  ascertained,  they 
all  rotate  on  their  axes ;  and  all  rotate  from  west 
to  east;  that  the  forms  and  movements  of  all, 
and  of  all  the  satellites,  are  conformed  to  one  set 
of  laws,  and  that  all  we  know  of  other  planets, 
points  to  a  fundamental  correspondence  and  identity 
between  them. 

This  conclusion  vastly  enlarges  our  field.  We  must  The  plan- 
think  of  each  of  the  planets  heated  up  to  a  fire-mist  ets  once 
condition.  It  is  easier  to  think  the  sun  also  heated 
to  such  condition,  since  he  is  at  present  not  so  far  re- 
moved from  it  as  the  planets.  Now,  when  all  these 
bodies  were  in  that  heated  condition  which  main- 
tained them  in  a  fire-mist  state,  the  whole  space  of 
the  solar  system  must  have  been  filled  with  fire-mist. 
Notice,  that  I  do  not  say  it  was  fire-mist  of  any 
specified  density.  The  density  of  vapor  depends  on 
the  proximity  of  the  liquid  floating  particles,  to  each 
other.  There  may  have  been  a  diffused  very  thin  gas 
also,  in  which  the  liquid  particles  floated.  Still,  I 
do  not  conceive  such  gas  necessary.  These  particles 
— some  of  which  may  even  have  been  solid— would 


252     Walks  and  Talks  in  the  Geological  Field. 

have  weight  smaller  than  imagination  can  conceive. 
They  were  not  particles  like  those  of  our  clouds,  in- 
fluenced by  the  powerful  attraction  of  a  vast  globe  of 
matter  not  half  a  dozen  miles  distant,  and  hence 
needing  some  buoyant  support.  These  fire-mist,  and 
perhaps  solid,  particles  were  attracted  only  by  each 
other,  and  by  the  great  common  aggregation  of  par- 
ticles. For  the  particles  in  the  neighborhood  of  the 
center  of  the  aggregation,  the  attraction  would  be 
nearly  equal  in  all  directions.  For  particles  millions 
of  miles  away,  an  excess  of  attraction  toward  the 
center  would  be  felt ;  but  the  force  would  be  incon- 
ceivably small.  So  the  mist  particles  were  practically 
suspended  in  space  and  required  no  gaseous  support. 
The  cooling  history  can  be  traced  no  farther  back. 
Such,  probably,  was  its  beginning.  But  I  do  not 
assume  that  the  matter  of  our  system  was  originated 
in  this  state.  We  may  be  able  to  trace  out  some 
remoter  antecedents  ;  but  if  that  can  not  be  done, 
I  am  perfectly  prepared  to  admit  that  matter  may 
have  entered  existence  as  a  fire-mist. 

Now,  another  thought  is  in  every  reader's  mind. 
This  point  has  been  reached  as  a  beginning  of  a 
history  of  cooling. 
Natural         From  this  point  a  natural  process  of  cooling  brings 

of  tiTeti0n  to  pass  a11  tne  events  in  our  system's  physical  history 
physical  —all  the  events  in  our  world's  history.  We  are  pro- 
xT^dnot  Pos*n£  to  sh°w  this,  and  trace  the  evolution  in  its 
abolish—  general  outlines. 

Suppose  we  call  the  fire-mist  the  absolute  begin- 
ning ;  there  are  certainly  three  things  which  are  not 
fire-mist,  and  require  explanation  infinitely  more 
than  a  fire-mist  condition  of  matter.  Without  these 


Gathering  World  Stuff.  253 

three  things,  there  would  never  be  a  cooling  history. 
These  things  are :   1.    MATTER— regardless  of  its  con-  Matter, 
dition.    2.    FORCE— and  that  in  its  various  forms.    3.  Force» 
METHOD — or  every  thing  would  be  plunged  in  chaos, 
and    forever    remain   there.     These    things    imply 
Power,  Intelligence,  Self-determination.    Where  self- 
determination  is  present,  there  is  Personality.    While 
the  origination  of  Matter,  Force,  and  Method  re- 
mains, there  is  still  need  of  a  Creator 


XXXVI.     GATHERING  WORLD  STUFF. 

WANDERING  GERMS  OF  WORLDS. 

COMETS  are  facts  of  observation ;  there  is  no  mis-  _ 

Comets, 
take  as  to  the  real  existence  of  such  bodies,  whatever 

they  be.  They  always  excite  our  admiration.  They 
are  full  of  wonder.  They  come  from  the  unsearch- 
able depths  of  space,  and  after  shining  in  our 
heavens  a  few  weeks  disappear  in  the  unsearchable 
depths.  What  is  their  origin?  What  their  end? 
Think  of  the  approach  of  one  of  these  mysterious 
messengers  from  the  infinite.  Before  discernible  to 
unaided  eyes,  the  astronomer  with  his  instrument 
detects  it  as  a  faint  luminosity  just  appeared.  For 
weeks  he  watches  its  changes.  Nightly  it  grows 
brighter.  It  is  approaching  ;  it  will  arrive.  Like 
the  head-light  of  a  locomotive  seen  at  first  as  a  lu- 
minous point  in  the  far  distance,  over  some  miles  of 
track,  gradually  growing  brighter— so  comes  the 
head-light  of  a  train  of  cosmical  matter  ;  so  grows 
its  luminosity  ;  with  such  a  stunning  demonstration 
of  physical  power  it  rushes  past  us,  and  sinks  into 


254     Walks  and  Talks  in  the  Geological  Field. 

infinite  distance  in  another  quarter  of  the  heavens. 
I  confess  it  is  impossible  to  contemplate  all  this  with- 
out a  feeling  of  awe. 

Would  that  the  mystery  of  the  comet  were  once 
unfolded  to  us  !  It  tantalizes  us  by  its  near  approach 
and  its  undiminished  inscrutableness.  But,  thanks 
to  intelligence  —  thanks  to  the  spirit  of  science — 
thanks  to  that  beneficent  constitution  of  the  universe 
by  which  it  gives  up  its  secrets  one  by  one,  to  the 
demands  of  intelligent  inquiry,  we  have  found  out 
something.  We  have  seen  comets  torn  to  pieces  by 
the  power  of  attraction— without  a  collision — by  the 
attractions  of  the  satellites  of  Jupiter.  This  was 
Bi-e'-la's  [Be-a'la]  comet,  and  each  fragment  thence- 
forward pursued  its  separate  path.  We  have  seen 
comets  so  shattered  and  disintegrated  by  the  pulls 
and  strains  to  which  they  were  subjected  in  our  sys- 
tem—in making  their  circuit  about  our  sun,  in  get- 
ting through  the  entanglements  of  Jupiter's  and 
Saturn's  attractions,  that  they  appeared  literally  to 
be  going  to  pieces  and  dividing  up  their  remains 
among  the  planetary  masses  of  the  system. 
Comets  The  comet,  in  short,  appears  to  be  essentially  a 
are  trains  train  of  stones  flying  with  three  thousand  times  the 
'velocity  of  the  railroad  "express."  The  smaller 
stones  more  resisted  than  the  larger  ones,  by  other 
matter  disseminated  through  space,  slacken  their 
motion  slightly,  and  are  struck  by  the  larger  stones 
with  velocities  exceeding  that  of  a  cannon  ball. 
Light  is  disengaged,  as  when  the  cannon  ball  strikes 
the  iron  target ,  and  thus  the  whole  cometary  train 
is  lighted  up.  The  nearer  it  approaches  the  power- 
fully attractive  bodies  of  our  system,  the  greater 


Gathering  World  Stuff.  255 

these  disturbances  become — the  intenser  the  lumi- 
nosity— the  more  extended  and  the  more  widened  the 
train  of  finer  materials.  But  do  not  think  this  train 
of  stones  is  the  so-called  luminous  "tail"  of  the 
comet.  The  tail  always  turns  away  from  the  sun ; 
the  dark  train  follows  in  the  path  of  the  comet.  The 
cause  of  the  tail  is  yet  a  mystery.  It  may  be  a  smoke 
of  luminous  particles  driven  off  by  the  intense  heat 
of  the  sun. 

The  comets  all  have  to  make  a  journey  around  the 
sun.  Some  of  them  remain  in  our  system  and  sub-  of  comets, 
ject  themselves  to  the  laws  of  the  planetary  family  ; 
but  others  can  not  be  induced  to  stay  ;  they  rush  on- 
ward with  such  velocity  that  all  the  power  of  the  sun 
and  planets  is  not  sufficient  to  stop  them.  They 
launch  out  from  our  remotest  shore,  on  the  limitless 
ocean  of  space  which  stretches  to  the  shores  of  other 
systems,  and  stretches  beyond,  farther  than  imagina- 
tion can  picture.  But  the  comet  which  becomes 
domiciled  in  our  system  seems  gradually  to  undergo 
disintegration,  and  by  and  by  its  borders  are  spread 
so  far  as  to  brush  the  atmosphere  of  some  planet 
when  passing  near  it.  Our  atmosphere  has  been 
thus  pierced  by  the  outlying  constituents  of  certain 
cometary  trains.  Sometimes  countless  thousands  of 
them  shoot  through  the  air.  These  missiles  move 
with  a  velocity  as  high  as  twenty  to  forty  miles  a 
second,  and  the  friction  and  condensation  resulting 
develop  sufficient  heat  to  render  the  missile  lumi- 
nous. 

We  call  it  a  meteor.    We  had  not  contemplated  Meteors 
the  meteor  as  a  burning  fragment  of  an  old  decayed 
comet.    But  some  of  our  most  splendid  meteoric  dis- 


256     Walks  and  Talks  in  the  Geological  Field. 

plays  have  resulted  from  clouds  of  meteoroidal  bodies 
which  have  been  quite  certainly  identified  with  rec- 
ognized comets.  At  certain  regular  intervals,  on  or 
about  the  sixteenth  of  November,  occurs  a  celebrated 
meteoric  shower  which  comes  from  a  meteoroidal 
train  or  cloud  that  has  been  identified  with  Tempel's 
comet — the  first  one  observed  in  1866.  Another  me- 
teoric shower  occurring  annually  about  tke  tenth  of 
August  has  been  identified  with  the  third  comet  of 
1862.  Also,  the  shower  which  occurs  on  the  twenty- 
seventh  of  November,  and  was  particularly  conspic- 
uous in  1885,  has  been  connected  with  Biela's  comet, 
first  observed  in  1826.  This  is  the  comet  which  was 
parted.  The  fragments  have  not  appeared  to  view 
during  several  revolutions ;  and  there  is  reason  to 
think  nothing  remains  but  dark  trains  of  stones. 
Radiant  So  much  is  pretty  well  settled.  There  are  nu- 
points.  merous  other  trains  of  meteoroidal  matters  which  we 
have  reason  to  regard  as  worn  out  comets.  In  fact, 
since  we  have  meteoric  displays  on  nearly  every 
night  of  the  year,  must  there  not  be  as  many 
meteoroidal  trains  as  there  are  distinct  radiant  points 
from  which  the  meteors  shoot?  One  train,  you 
understand,  might  touch  our  atmosphere  on  one  side 
and  another  on  a  different  side.  To  our  eyes,  the 
motions  of  the  ignited  meteors  would  be  in  all  direc- 
tions from  the  region  of  contact.  That  region  would 
be  projected  on  some  constellation,  and  would  remain 
fixed  there  though  the  earth  rotated.  So  each  radi- 
ant point  would  imply  a  different  contact— a  different 
swarm ;  and  accordingly  there  must  be  a  hundred 
swarms  or  more  which  touch  our  atmosphere. 
But  reflect  now,  that  a  meteoroidal  swarm  is  de- 


Gathering   World  Stuff.  257 

scribing  an  orbit  about  the  sun,  and  we  learn  of  its  Multi. 
existence  simply  because  it  happens  to  pass  very  near  tudes  of 
the  orbit  of  the  earth,  and  happens  to  pass  at  the  jjjjj£jj[g 
time  when  the  earth  is  there.     If  it  passed  at  a  little 
greater  distance,  or  passed  always  when  the  earth  was 
absent,  we  should  know  nothing  of  the  swarm— save 
possibly  as  a  comet,  if  not  yet  too  much  disintegrated 
to  emit  light.    How  many  chances  against  this  favor- 
able   concurrence   of  positions !    How    many  more 
swarms  there  must  be  which  never  reveal  to  us  their 
existence!     When  we  reflect  that  we  are  brushed 
by  say  a  hundred  of  them  annually,  must  we  not 
conclude  that    there   are    thousands    which    sweep 
through  space  unnoticed  ?    I  think  the  spaces  around 
us  must  be  full  of  their  motions.    Were  our  vision 
perfect,  we  should  see  the  heavens  clouded  by  swarm- 
ing meteoroids  darting  In  every  conceivable  direction 
—like  the  clouds  of  home-returning  swallows  in  the 
dusk  of  a  summer  evening.    These  particles  of  cos- 
mical  matters— these  clouds  of  cosmic  dust  intervene 
between  us  and  the  sun,  and  must  shut  out  a  large 
proportion  of  the  solar  light  and  heat.    We  are  told 
by  Professor  J.  P.  Langley  that  not  more  than  half  Their  ef_ 
the  sun's  radiant  force  reaches  the  earth.    They  tell  feet  on 
us  the  remainder  is  "absorbed"  by  the  atmosphere  ®nt  n™t  *~ 
and  the  dust  which  floats  there ;  but  much  of  the  and  light, 
absorption  must  be  accomplished  by  the  cosmic  mat- 
ter which  exists  beyond  the  atmosphere.    The  ab- 
sorption thus  effected  would  be  still  greater  to  the 
inhabitants  of  Venus  and  Mercury,    if  inhabited ; 
since  cosmic  matter  must  be  more  accumulated  in 
the  nearer  neighborhood  of  the  sun.    Thus  the  tem- 
perature on  those  planets  would  be  lower  than  their 


258      Walks  and  Talks  in  the  Geological  Field. 

proximity  to  the  sun  would  lead  us  to  suppose.  On 
the  same  principle,  the  solar  emanations  at  Mars  or 
Saturn  would  be  greater  than  their  distances  from  the 
sun  would  lead  us  to  suppose. 

Meteoric        We  have  seen  the  meteor  ignited  in  the  upper  air. 

dust.  \ye  have  seen  its  bright  streak  vanish  while  we  gazed. 
The  little  body  was  melted—  it  was  vaporized.  While 
passing  through  the  space  measured  by  its  line,  it 
changed  from  a  cold  stone  to  shining  dust,  and  then 
a  darkened  dust  left  floating  in  the  upper  strata  of 
the  atmosphere.  But  though  unseen,  the  meteoric 
dust  still  exists.  It  now  belongs  to  the  earth.  It 
will  be  wafted  to  and  fro  by  the  winds  ;  it  will  come 
down,  after  some  months,  and  contribute  some  new 
material  to  the  earth.  Some  of  these  atoms  will  fall 
on  the  ocean  ;  most  of  them  will  fall  there  ;  and  after 
other  months  they  will  settle  to  the  bottom  and  min- 
gle with  the  ooze  which  is  there  accumulating.  You 
will  remember  our  walk  under  the  sea  (Talk  X.),  and 
the  comet-dust  which  we  found. 

which   we  have   reached   reveals   the 


Summary 

boundless  space  around  us  well  stocked  with  material 
particles.  They  are  not  uniformly  distributed  ;  by 
their  mutual  attractions  they  are  gathered  into 
swarms.  The  swarms  are  not  motionless  ;  they  are 
drawn  toward  every  attracting  body  in  the  universe. 
They  are  not  changeless  ;  by  degrees  each  swarm 
grows  as  long  as  it  has  a  separate  existence,  by  the 
accession  of  other  swarms.  As  these  swarms  sail 
majestically  through  the  ocean  of  immensity,  some 
are  brought  under  the  control  of  distant  suns,  and 
start  on  long  journeys  to  pay  their  flying  visits. 
They  approach  now  as  comets.  If  they  are  induced 


The  Whirling  Fire-mist.  259 

to  circle  perpetually  about  given  suns,  they  finally  go 
to  pieces  again,  and  the  parts  are  either  drawn  to 
their  central  suns,  or  distributed  among  the  planets. 
If  they  escape  from  the  systems  entered,  they  steady 
themselves  across  the  gulfs  of  space  which  separate 
systems,  and  in  the  progress  of  centuries,  float  into 
other  ports  and  new  excitements. 

But  some  of  these  swarms  remain  floating  in  the  Nebulae, 
depths  of  extra-firmamental  space,  and  gather  to 
themselves,  by  their  increasing  power  of  attraction, 
all  other  swarms  and  particles  from  their  region  of 
immensity.  They  become  Nebulas.  They  are  lu- 
minous because  pounded  by  the  fall  of  other  swarms, 
and  lighted  by  the  collisions  of  their  internal  parts. 
They  are  composed  of  matters  solid,  liquid,  and  gas- 
eous. They  rotate.  Poised  in  space,  the  impacts  of 
gathering  matters  have  started  them  on  their  axes 
of  motion.  There  they  are  before  our  eyes.  The 
background  of  the  heavens  is  phosphorescent  with 
the  glow  of  these  distant  fields  of  world-stuff.  Each 
is  a  living  picture  of  that  primordial  state  in  which 
we  fancy  the  matter  of  the  solar  system  existed  when 
that  history  of  cooling  began  which  we  endeavored 
to  trace  to  a  starting  point. 


XXXVII.     THE  WHIRLING  FIRE-MIST. 

NEBULAR  THEORY  OF  WORLD   ORIGIN. 

BEHOLD  the  matter  of  a  solar  system  in  the  form  The  golar 
of  a  nebula.    Poised  in  the  midst  of  space,  it  tends  system 
to  a  globular  form  ;  but  the  attraction  of  its  own  cen-  °"£^ 
ter  is  so  distant  as  to  be  feebly  felt  at  the  remote 


260     Walks  and  Talks  in  the  Geological  Field. 

periphery  of  so  tenuous  a  mass.  The  late  accessions 
of  nebulous  stuff  have  left  superficial  irregularities — 
like  those  in  the  clouds  which  float  in  our  atmos- 
phere. They  subside  with  comparative  slowness ; 
but  yet  they  tend  to  disappear.  This  vast  empire  of 
world-stuff  rotates,  but  a  million  of  years  may  flee 
away  before  one  revolution  is  completed.  With 
eternity  at  command  all  finite  intervals  of  time  are 
Structure  zero-  I  cannot  answer  the  question  whether  a  gas- 
eous constitution  pervaded  all  parts  of  this  nebula. 
I  think  it  probable  that  portions  of  the  included 
space  were  filled  with  gas.  I  think  such  portions 
may  have  been  bounded  by  the  sphere  on  which  the 
elasticity  of  the  gas  was  equalized  by  opposing  at- 
tractions. There  was  already  fire-mist — fine  liquid 
particles  suspended  in  gases  or  poised  between  coun- 
ter attractions.  There  were  probably  stones  and  con- 
cretions of  iron  hanging  suspended  through  the 
mass.  It  is  not  at  all  supposable  that  the  entire  space 
within  the  periphery  of  the  nebula  was  occupied. 
There  may  have  been  spaces  hundreds  or  thousands 
of  miles  wide,  not  filled  with  anything  but  the  all- 
pervasive  ether — if  that  exists.  I  do  not  conceive  a 
continuous  medium  so  unimaginably  thin  as  would 
result  from  the  expansion  of  the  matter  of  the  solar 
system  uniformly  through  a  sphere  bounded  by  the 
orbit  of  Neptune. 

Con-  If  tnis  mass  is  heated,  it  radiates  heat  into  sur- 

traction  rounding  space,  and  the  heated  parts  contract.  If 
the  parts  are  still  gathering  themselves  nearer  to  the 
distant  center  of  gravity,  the  whole  mass  contracts. 
If  the  time  ever  arrives  when  the  parts  gathering 
toward  the  center  of  gravity  are  balanced  by  mutual 


The  Whirling  Fire-mist. 


resistances,  or  by  reaction  of  heat,  then  further  loss 
of  heat  will  result  in  contraction  of  the  whole  mass. 
In  either  event,  the  mass  contracts.      If  a  rotating  and 
body  contracts,   its  rate  of  rotation  is   accelerated,  rotation. 
This  is  one  of  the  necessary  laws  of  matter.    A  ro- 
tating sphere  of  tenuous  matter  undergoes  some  flat- 
tening at  the  poles ;   as  the  velocity  of  rotation  in- 
creases, the  polar  flattening  increases ;  the  equatorial 
protuberance   increases.     The  earth  is  equatorially 
protuberant  because  it  rotates. 

When  a  body  rotates  on  its  axis,  the  parts  around 
the  equator  experience  a  tendency  to  fly  off,  which 
is  greater  than  such  tendency  on  other  parts  of  the 
surface.  If  the  earth  were  to  rotate  seventeen  times 
as  rapidly  as  it  does,  bodies  at  the  equator  would 
have  no  weight.  In  the  rotating  nebula  which  we 
are  considering,  the  centrifugal  tendency  of  the  equa- 
torial parts  diminishes  their  weight,  and  the  undi- 
minished  weight  of  the  polar  parts  presses  the  equa- 
torial out  in  a  bulge. 

Meantime  the  nebula  contracts  and  the  rate  of  ro-  Increasing 
tation  continues  to  be  accelerated.     Evidently  the  contrac- 
time  will  arrive  when  parts  on  the  equator  will  have  Station, 
acquired  a  tendency  to  fly  off  just  equal  to  the  at- 
traction by  which  they  had  been  held  in  their  places. 
If  contraction  still  continues,  as  it  must  in  a  cooling 
mass,  the  peripheral  parts,  balanced  between  equal 
centrifugal  and    centripetal    forces,  will   not   move 
either  toward  the  center  or  from  the  center.    What 
should  make  them  ?    Those  parts  will  remain  where 
they  are,  and  the  parts  within  will  withdraw  from 
the  equatorial  parts.    That  is,  a  ring  will  be  disen-  Formation 
gaged— not  thrown  off.    The  ring  will  retain  the  ro-  of  a  rins- 


262      Walks  and  Talks  in  the  Geological  Meld. 

tation  which  it  had,  and  the  residual  mass  will  con- 
tinue to  cool  and  accelerate  its  rotation  within  the 
ring. 

What  will  happen  to  the  ring  ?  Perhaps  you  have 
seen  the  ring  of  white  smoke  resulting  from  the  ex- 
plosion of  a  soap  bubble  inflated  with  phosphureted 
hydrogen  ;  what  happened  to  that  ?  It  floated  as  a 
ring  till  external  disturbances  caused  its  rupture, 
Ring  rup-  wnen  the  smoke  became  a  simple  cloud.  The  cosmic 
turesand  ring  will  experience  the  same  fate.  This  nebula  is 
spheroidal  no*  nanSmg  m  the  universe  alone.  All  space  is  ani- 
mated by  moving  masses  and  groups  of  masses. 
Comets  are  darting  to  and  fro.  Distant  suns  are 
tugging  steadily,  even  if  feebly,  on  the  parts  of  this 
ring.  Somehow,  in  the  course  of  ages,  the  balance 
of  the  ring  will  be  destroyed.  An  excess  of  matter 
will  be  drawn  to  one  side  ;  and,  as  a  consequence,  all 
the  matter  will  be  drawn  to  that  side.  Or,  perchance, 
the  unequal  attraction  may  set  up  a  wabbling  rota- 
tion of  the  ring.  Then,  by  the  laws  of  matter,  the 
wabbling  will  increase  until  the  ring  is  ruptured. 
That  will  cause  all  the  matter  to  gather  to  the  unbro- 
ken side. 

Motions  Thus,  from  one  cause  or  another,  the  ring  of  nebu- 
oftnis  lous  matter  must  become  a  sphere  of  nebulous  mat- 
ter. Its  distance  from  the  original  center  is  the  dis- 
tance of  the  ring.  This  sphere  moves  in  an  orbit 
occupying  nearly  the  place  of  the  ring.  This  sphere 
rotates  on  an  axis,  and  the  direction  of  the  rotation 
will  be  determined  largely  by  the  width  of  the  ring 
from  which  it  was  formed,  and  relative  velocities  of 
the  outer  and  inner  circumferences  of  the  ring.  In 
most  cases,  the  direction  of  the  rotation  would  be  the 


The   Whirling  Fire-mist.  263 

same  as  the  direction  of  the  mass  in  its  orbit ;  but  if 
the  diameter  of  the  orbit  is  relatively  very  great,  the 
direction  of  rotation  may  be  the  reverse  of  the  mo- 
tion in  the  orbit. 
This  resultant  spheroid  is  to  become  a  planet.    The  continu- 

residual  mass  continues  its  history  as  begun.    Bv  ation  of 

the  process 
and  by,  another  ring  is  detached,  and  in  the  course  upon  the 

of  ages,  this  also  becomes  a  spheroid  destined  to  be-  central 

body. 

come  another  planet.  Meantime,  as  the  disengage- 
ment of  a  new  ring  diminishes  the  mass  of  the  cen- 
tral body,  the  centripetal  force  exerted  on  the  first 
planet  is  diminished.  The  centrifugal  force  there- 
fore increases  its  distance  from  the  common  center. 
This  diminishes  its  angular  velocity,  and  therefore 
the  centrifugal  force,  and  thus  the  centripetal  and 
centrifugal  forces  become  equal  again— both  dimin- 
ished. 

Thus  two  planetary  masses  come  into  existence.  Theresult. 
By  repetitions  of  the  same  process,  a  complete  series  ing  pian- 
of  planetary  masses  becomes  scattered  over  the  dis-  ets  vary' 
tance  between  the  original  periphery  and  the  center  ; 
and  at  each  occasion  of  planetary  birth,  all  the  older 
planets  recede  a  certain  distance  farther  from  the 
center,  and  undergo  a  certain  retardation  in  their 
orbital  velocities.  The  different  planetary  masses, 
however,  do  not  possess  equal  densities  ;  they  are  not 
composed  of  such  ingredients  as  to  furnish,  on  cool- 
ing to  a  given  temperature,  the  same  proportion  of 
solid,  liquid,  and  gaseous  constituents.  Before  planet 
making  began,  we  may  suppose  the  heavier  constitu- 
ents of  the  general  mass  had  gravitated  to  the  cen- 
tral regions  ;  while  the  lighter  constituents  remained 
nearer  the  periphery.  If  so,  the  first  planets  sepa- 


264      Walks  and  Talks  in  the  Geological  Meld. 

rated  would  contain  more  of  the  substances  which, 
at  temperatures  familiar  to  us,  make  gases  and  water. 
Similarly,  the  later  planets  disengaged  would  ac- 
quire a  larger  proportion  of  the  substances  which 
form  solid  rocks.  In  the  case  of  the  earth  we  may 
suppose  the  greater  part  was  rock-making  material, 
since  the  earth's  specific  gravity  is  so  high ;  but 
watery  stuff  in  sufficient  amount  to  provide  oceans 
and  rains,  went" off  with  the  rock  material,  and  with 
these,  the  lighter  stuff  for  an  atmosphere.  But  in 
the  case  of  Venus,  most  of  the  stuff  was  rock-mate- 
rial, if  not  the  whole  of  it ;  while  with  Mercury  it 
seems  probable  that  little  water-stuff  was  included. 
In  the  opposite  direction,  Saturn,  Uranus,  and  Nep- 
tune must  have  received  a  large  excess  of  water  and 
atmospheric  stuff.  It  is  rational  to  suppose  that 
their  oceans  have  always  covered  the  whole  land,  as 
ours  does  more  than  half.  In  fact,  these  bodies  must 
be  composed  chiefly  of  water  and  atmosphere ;  as 
their  specific  gravities  are  low  as  water  and  cork. 
Each  pur-  ®°>  *n  t^ie  nist°ry  °f  our  system,  the  work  went  on 
sues  an  in-  as  long  as  the  conditions  existing  permitted  the  cen- 
tral  mass  to  detach  rings.  Meanwhile,  the  planetary 
masses  entered  severally  on  their  separate  careers. 
Each  career  was,  in  effect,  a  history  of  cooling. 
They  did  not  proceed  with  equal  pace,  since  some, 
with  larger  mass  than  others,  had  more  heat  to  radi- 
ate, and  the  power  to  radiate  was  not  in  proportion 
to  the  mass  but  to  the  surface.  Hence,  some  of  the 
older  planets  are  less  advanced  than  the  earth,  be- 
cause so  much  larger  ;  while  Mars,  I  imagine,  is  more 
advanced,  both  because  smaller  in  mass  and  older. 
Now,  during  the  habitable  stage  of  the  earth,  the 


The  Primeval  Storm.  265 

sun  remains  the  residual  mass  of  the  ancient  nebula. 

The  sun  is  a  relic  of  the  primordial  fire-mist.    The  Thestm 
sun  is  historian  of  a  mighty  past.    He  is  more  to  us  a  relic. 
than  a  source  of  bodily  comfort.    He  sustains  rela- 
tions to  our  intelligence.    He  proclaims  and  exempli- 
fies our  material  origin.    He  responds  to  our  anxious 
inquiry  concerning  long  histories  which  were   en- 
acted in  the  ages  unnumbered  ;  before  man  existed. 


XXXVIII.    THE  PRIMEVAL  STOEM. 

ORIGIN  OF  THE  OCEAN. 

LET  us  now  attempt  to  trace  the  physical  history 
of  that  planetary  mass  which  was  destined  to  become  tory  of  the 

the  earth.    We  contemplate  it  in  a  state  of  fire-mist.  cooline 

earth  to 
Here   are  no  water,  no  atmosphere,  no    rocks,   no  be  traced. 

organic  forms.  In  this  fire-mist,  however,  were  the 
elements  of  all  the  forms  of  matter  which  were  to 
exist  in  or  upon  the  earth,  in  the  long  progress  of 
its  history.  The  moon,  on  what  seems  to  me  the 
most  probable  view,  had  already  been  separated,  but 
was  still  much  nearer  the  earth  than  at  present,  and  An  eartll 
performed  its  revolution  in  a  shorter  period.  The  offlre- 
earth's  axial  rotation  was  correspondingly  more  mist' 
rapid.  Earth  and  moon  mutually  exerted  powerful 
tidal  actions.  Each  changed  the  form  of  the  other 
from  the  simple  oblate  spheroid  shaped  by  rotation, 
to  a  prolate  modification  of  this.  That  is,  each  by 
its  attraction  drew  the  other  into  a  form  slightly 
elongated.  The  elongation  was  a  "  deformative  tide  " 
or  "  bodily  tide."  Of  course,  the  moon  was  much 
more  deformed  than  the  earth.  The  tidal  elevation 


266     Walks  and  Talks  in  the  Geological  Field. 

on  the  moon,  at  its  present  distance,  is  one  hundred 
and  thirty-four  times  that  on  the  earth.  Those  tidal 
interactions  have  always  existed,  and  still  exist. 
Fiery  pre-  *  can  no^  affirm  that  the  matter  of  the  earth  was 
cipitation.  now  all  fire-mist  suspended  in  a  continuous  gas. 
There  must  always  have  been,  since  fire-mist  first  be- 
gan to  form,  a  tendency  of  the  liquid  particles  to 
coalesce,  and  this  tendency  would  increase  with  the 
progress  of  cooling.  A  time  would  arrive  when 
drops  thus  formed  would  begin  to  descend  by  gravity 
toward  the  center  of  the  fire-mist  sphere.  They  are 
not  to  be  conceived  as  dropping  with  accelerated 
velocity,  like  bodies  falling  through  space,  since 
within  the  sphere,  the  central  attraction  continually 
diminishes  as  the  distance  from  the  center  dimin- 
ishes. At  the  center  the  attraction  is  equal  in  all 
directions.  But  the  molten  liquid  began  finally  to 
accumulate  at  the  center.  It  shaped  itself  in  a  globe 
A  molten  wnicn  grew  as  the  fiery  precipitation  continued.  In 
globe.  the  course  of  time,  the  greater  part  of  the  fire-mist 
had  rained  down,  and  a  molten  earth  stood  forth 
in  space,  glowing  with  a  white  heat,  and  enveloped 
in  a  hot  and  heterogeneous  atmosphere  which  con- 
tained all  the  substances  vaporized  at  the  tempera- 
ture then  existing. 

This  earth  This  self-luminous  earth  was  a  sun  in  reference 
as  a  sun.  to  the  moon.  The  moon  had  already  advanced  to 
a  stage  corresponding  with  that  called  habitable,  and 
the  light  afforded  its  conceivable  inhabitants  was 
twelve  times  as  intense  as  that  received  from  the  sun 
— assuming  the  distances  the  same  as  at  present. 
The  earth  was  a  star,  and  had  long  been  a  star,  to  the 
inhabitants,  if  any,  of  remote  orbs.  Perhaps  they 


The  Primeval  Storm.  267 

had  descried  it  with  their  instruments ;  perhaps  it 
had  been  noted  in  their  catalogues,  with  latitude  and 
longitude  thus  and  so.  The  sun  was  now  shedding 
its  superfluous  light  and  heat  on  a  planet  which  was 
yet  itself  a  sun. 

The  molten  earth  continued  to  waste  its  heat.  The  rp^  form. 
exposed  surface  materials,  as  fast  as  chilled,  sank  ing  crust, 
into  the  interior  by  their  superior  density,  and  hotter 
materials  rose  to  the  surface.  There  was  a  circulation 
between  the  surface  and  interior.  This  prevented  any 
extreme  difference  in  temperature.  But  some  greater 
reduction  was  always  experienced  at  the  surface. 
It  was  at  the  surface,  therefore,  that  the  first  solidi- 
fication took  place.  At  this  juncture,  the  sinking 
of  the  coolest  portions  ceased.  Rock-materials,  like 
all  others  which  crystallize  on  solidifying,  undergo 
a  slight  enlargement  in  the  act  of  becoming  solid.  A 
crust,  therefore,  began  to  form  over  the  liquid  planet. 
Like  ice  on  the  lake,  it  floated.  If  you  go  to  the 
crater  of  Kil-au-e'-a,  in  Hawaii,  you  will  find  a  vast 
lake  of  molten  rock,  the  surface  of  which  has  frozen 
into  a  crust  like  that  which  formed  over  the  earth's 
surface.  There  is  no  mistake  in  the  opinion  that  the 
cooling  crust  would  float. 

The  tidal  protuberance  caused  by  the  moon  never  i-idai 
ceased.    The  side  toward  the  moon  was  always  up-  action  in 
lifted.    As  the  earth  turned  on  its  axis,  a  different  th'     nwt* 
part   of  the  terrestrial  surface  was  raised  at   each 
moment.     The  great  tidal  swell  swept  past  every 
point  of  the  surface  at  every  revolution  of  the  planet. 
Thus  the  forming  crust  was  alternately  uplifted  and 
depressed.    Much  fracturing  of  the  crust  must  have 
resulted.    The  crushing  and  grinding  of  the  frag- 


268     Walks  and  Talks  in  the  Geological  Field. 


inents  displaced  them ;  great  lateral  pressures  tilted 
them  on  edge  and  piled  them  up  in  enormous  hum- 
mocks. The  scene  must  have  been  analogous  to  those 
in  Baffin's  Bay  and  the  Arctic  Ocean,  of  which  ex- 
plorers bring  us  exciting  accounts.  The  surface  of 
the  earth  assumed  the  rugged  character  of  a  vast 
"floe." 

Continued  I  imagine  this  floe  was  still  luminous,  except  in  the 
cooling  ai-  projecting  crags.  Over  this  still  glowing  terrestrial 
surface,  sunlight  was  still  shed.  Who  can  calculate 


last  the 
precipi- 
tation of 
water. 


the  length  of  the  seons  which  passed  while  such  a 
scene  of  desolation  reigned?  All  the  time,  the 
process  of  cooling  went  forward.  While  the  white- 
hot  crust  subsided  to  a  red-hot  temperature,  the  at- 
mosphere became  less  parched.  While  the  shadows 
of  a  darkening  crust  tipped  the  most  salient  crags, 
the  upper  air  grew  continually  freer  from  the  terrific 
heat  which  had  swept  outward  from  the  terrestrial 
surface.  As  the  temperature  of  the  air  subsided, 
there  were  precipitations  of  various  substances  which 
could  maintain  their  gaseous  condition  no  longer. 
At  length  it  came  the  turn  of  water  to  begin  to  con- 
dense. It  had  long,  already  existed  as  an  invisible 
gas.  Now,  with  an  upper  air  temperature  passing 
below  212°,  the  invisible  steam  began  to  become 
visible  vapor. 

I  have  often  wished  I  might  have  beheld  the  scene. 
I  think,  could  I  have  been  present,  I  should  have 
witnessed  something  like  this  :  The  forming  vapor 
in  the  upper  air  reveals  its  presence  in  a  thin  and 
gauzy  haze,  like  that  which  overspread  the  sky  when 
the  ashes  of  Kra-kat'-o-a  were  floated  round  the 
world.  The  veil  grows  thicker  from  age  to  age.  It 


The  Primeval  Storm. 


is  now  a  "cirrus"  sheet  of  cloudy  vapor  like  that 
which  the  anti-trades  drive  up  from  our  southwestern 
horizon.  The  contour  of  the  round  sun  is  blurred ; 
the  intensity  of  his  ancient  ray  is  softened.  In- 
deed, his  light  is  dimmed  ;  the  haze  is  becoming  a 
cloud.  A  twilight  approaches ;  the  shade  deepens. 
The  world  is  enveloped  in  a  cloudy  pall ;  the  lurid 
light  of  the  decaying  fires  of  the  crust  reddens  the 
overarching  canopy.  The  sun  is  quenched ;  the 
world  hangs  in  shadow  which  forms  the  first  night 
which  ever  visited  its  surface.  "  In  the  beginning  " 
there  was  "light"  ;  now  "darkness  is  upon  the  face 
of  the  deep,"  and  a  denser  darkness  impends. 

The  burdened  clouds  drop  rain.  The  o'erburdened  Battle  be- 
clouds discharge  a  storm  of  rain.  The  drops  de-  tween  flre 
scend  into  the  lower  and  heated  strata  of  the  atmos- 
phere, and  are  dissipated  into  vapor  which  rises 
to  the  clouds  to  be  again  condensed.  Continual  rains 
descend ;  but  the  hot  air  dries  them  up  and  sends 
them  back  to  the  bosom  of  the  clouds.  There  is  a 
battle  in  mid-air  between  the  powers  of  water 
marshaled  above,  and  the  powers  of  heat  intrenched 
behind  the  rocky  ramparts  below.  But  the  powers  of 
water  are  destined  to  prevail. 

Meantime  the  equilibrium  of  the  electricities  is  dis- 
turbed. The  friction  of  ascending  vapors  and  de- 
scending rains  develops  electrical  phenomena.  Here, 
in  this  storm  of  the  ages,  the  dazzling  glare  of  ten 
thousand  lightning  gleams  sheds  an  infernal  tinge 
over  the  murky  world  ;  and  the  responsive  voices  of 
ten  thousand  thunders  split  the  welkin  with  their  de- 
tonations. While  this  fury  and  chaos  reign,  the  line 
of  battle  sinks  to  the  hot  surface  of  the  earth,  and  all 


270     Walks  and  Talks  in  the  Geological  Meld. 

at  once  the  attacking  waters  are  volatilized  in  ten 
thousand  explosions,  which  rend  the  elements. 

The  culmination  of  the  great  eeonic  storm  is  passed. 
The  powers  of  fire  are  vanquished  ;  the  waters  gather 
over  the  heated  crust.  They  are  furious  with  effer- 
vescence and  ebullition,  but  they  hold  possession. 
On  all  sides  rise  columns  of  steam  from  a  boiling 
ocean.  The  atmosphere,  once  so  arid,  is  now  soaked 
with  vapor.  The  skies  still  drip  with  rains,  but  the 
gloom  is  not  so  dense.  There  seems  to  be  a  day- 
break on  the  scene.  The  exhaustion  of  the  clouds 
A  univer-  proceeds  ;  and  now  behold,  it  is  dawn.  A  new  cos- 
sal  ocean.  mje  day  is  rising  on  the  flooded  world.  The  volume 
of  the  ocean  swells  ;  it  has  no  shore.  The  clouds,  fed 
by  the  vapors  of  a  heated  ocean,  are  not  dispersed ; 
but  a  brightening  glow  heralds  promises  of  a  new 
age.  The  years  speed  on,  and  the  alternations  of 
night  and  day  are  discernible.  The  years  speed  on, 
and  expectation  waits  for  some  glorious  denouement. 
Behold,  it  arrives.  The  sun,  in  his  daily  circuit  about 
the  world  so  long  lost  to  him,  rose  one  day  in  the 
eastern  sky,  and  a  broad  rift  in  the  clouds  let  in  a 
golden  beam  of  sunlight,  direct  upon  the  waters 
which  enwrapped  the  earth. 

How  changed  the  scene  since  last  those  rays  fell 
useless  on  the  scorched  and  glowing  crust.  Then 
the  self-luminous  earth  cast  no  shadow,  and  there 
was  no  night.  Now,  one  hemisphere  is  in  darkness 
and  the  other  is  in  sunlight.  Now  for  the  first  time, 
as  the  earth  rolls  on  its  axis,  the  succession  of  night 
and  day  becomes  possible.  Now,  for  the  first  time, 
the  sun  becomes  "  the  ruler  of  the  day "  and  the 
moon  of  the  night. 


The  War  in  the  Ocean.  271 


XXXIX.    THE  WAR  IN  THE  OCEAN. 

THE  EARLIEST  STRATA. 

A  SHORELESS  ocean  now  enwrapped  the  world.  It  Thechem- 
was  not  a  placid  summer  expanse  overhung  by  bright  istry  of 
skies  and  swarming  with  happy  sentient  creatures,  v^sea™ 
The  rains  which  supplied  the  ocean  had  washed  from 
the  atmosphere  certain  acid  gases — especially  sul- 
phuric, chlorhydric,  and  carbonic — and  these  per- 
vaded the  water  now  resting  over  the  earth.  The  fire- 
formed  crust,  however,  on  which  the  ocean  rested, 
was  composed  chiefly  of  silicates  of  somewhat  com- 
plex constitution,  but  largely  silicates  of  alumina, 
potash,  soda,  lime,  and  magnesia.  Now  when  the 
hot  acid  waters  came  in  contact  with  these  silicates, 
certain  reactions  immediately  began.  The  silicates 
were  decomposed  ;  the  alkaline  bases,  potash,  lime, 
and  so  forth,  were  taken  up  by  the  free  acids,  form- 
ing chlorides  of  potassium,  calcium,  sodium,  mag- 
nesium ;  as  also  sulphates  and  carbonates  of  potash, 
soda,  magnesia,  and  lime.  Now  some  of  these  re- 
sulting compounds  were  soluble,  and  remained  dis-  Soluble 
solved  in  the  sea- water.  Such  were  the  chlorides  and 
sulphates,  and  the  carbonates  of  potash  and  soda. 
Thus  the  water  of  the  primitive  ocean  became 
charged  with  sulphate  of  soda,  or  Glauber's  salt ;  sul- 
phate of  lime,  or  gypsum  ;  sulphate  of  magnesia,  or 
Epsom  salts ;  also  with  chloride  of  sodium,  or  com- 
mon salt ;  and  the  other  chlorides,  which  are  the  bit- 
ter impurities  in  the  sea. 


272      Walks  and  Talks  in  the  Geological  Field. 

Precipi-  But  others  of  the  resulting  compounds  were  but 
tetes-  little  soluble,  and  were  therefore  precipitated  to  the 
bottom;  what  were  they?  Carbonate  of  lime  and 
carbonate  of  magnesia.  The  first  is  limestone,  and 
the  second  is  generally  mixed  with  the  first,  forming 
dolomite.  That  is,  a  layer  of  calcareous  material  was 
spread  over  the  sea-bottom.  It  was  a  chemical  pre- 
cipitate, not  a  sediment  in  the  geological  sense.  Two 
other  constituents  were  added  to  the  material  spread 
over  the  bottom.  I  stated  above  that  the  primitive 
crust  contained  silica  and  alumina  ;  what  became  of 
these  when  the  original  partners  had  to  sunder  con- 
nections? Potash,  soda,  lime,  magnesia  we  have 
traced  to  their  destinations  ;  but  silica  and  alumina  are 
left  outstanding.  Now,  probably,  these  concluded  to 
form  a  partnership  for  themselves  ;  and  so  silicate 
of  alumina  resulted.  This  being  insoluble  must  have 
fallen  to  the  bottom.  It  may  have  mingled,  in  some 
places,  with  the  calcareous  precipitates  and  it  may  in 
other  places  have  been  bedded  by  itself.  In  the  lat- 
ter case,  beds  of  argillite  would  result.  With  the  sil- 
ica and  alumina  some  potash  may  in  other  cases, 
have  combined ;  and  thus  would  be  formed  a  min- 
eral known  as  potash  feldspar,  or  common  feldspar. 
If  soda  or  lime,  instead  of  potash,  united  with  the 
silica  and  alumina,  the  result  was  simply  another 
species  of  feldspar.  The  feldspars  are  very  abundant 
in  the  oldest  rocks. 

But  perhaps,  again,  some  of  the  outstanding  silica 
and  alumina  concluded  not  to  combine  together. 
Then  the  alumina  would  simply  remain  free  alumina, 
to  mix  with  any  of  the  other  compounds  produced, 
or  form  by  itself  a  bed  of  pure  clay  ;  and  the  silica 


The  War  in  the  Ocean.  273 

would,  in  a  similar  way,  mix  with  other  substances 
or  form  by  itself  beds  of  pure  quartz. 

We  may  inspect,  now,  the  oldest  rocks  accessible  to  The  oldest 
investigation,  and  see  if  they  are  the  kinds  which  rocks 
should  be  expected,  according  to  the  above  reasoning.  are  not 
Yes,  in  a  general  way  they  are.    Feldspars  are  every-  such,  but 
where  disseminated  in  the  bottom  rocks.    There  are  ^^ 
great  beds  of  crystalline  limestone,  and  of  argillites.  them. 
There   are   micas,    hornblende,    and   augite,    all   of 
which,  like  the  feldspars,  are  essentially  silicates  of 
alumina  and  other  bases.    But  here,  also,  are  con- 
glomerates, composed  of  rounded  or  angular  frag- 
ments of  older  rocks.    Here,  indeed,  are  vast  forma- 
tions of  quartzites,  but  they  are  formed  of  grains, 
instead  of  being  those  purely  vitreous  masses  which 
would  result  from  the  precipitation  of  free   silica. 
But  each  separate  grain  is  such  vitreous  quartz,  and 
it  appears  as  a  fragment  of  some  rock  in  which  the 
whole  mass  was  purely  vitreous.    At  some  time  then, 
earlier  than  the  formation  of  these  granular  quartz- 
ites, there  were  formed  quartzites  not  composed  of 
grains,  but  continuous  like  a  mass  of  glass.    We  have 
to  conclude  that  the  oldest  rocks  accessible  are  not 
remnants  of  the  primeval  precipitates.    This  is  the 
conclusion  pointed  out  also  by  the  presence  of  con- 
glomerates. 

Let  us  trace  further  the  necessary  succession  of 
events.  The  chemical  war  is  now  settled  by  treaty  of 
peace ;  but  the  rains  of  a  geologic  spring-time  are 
still  frequent  and  copious.  The  tides  and  waves  stir 
up  the  fine  particles  resting  on  the  bottom,  and  these 
float  ofT  to  the  deeper  situations,  where  they  subside 
as  sediments  —  fragmental  sediments.  This  conse- 


274      Walks  and  Talks  in  the  Geological  Field. 


quence  of  unequal  depth  in  different  parts  of  the 
shallow  ocean  is  augmented  in  course  of  time,  by  the 
formation  of  wrinkles  in  the  crust.  These  resulted, 
as  explained  in  Talk  XX.,  from  the  lateral  pressure 
due  to  the  contraction  of  the  earth  within  the  crust. 
This  was  an  incident  of  cooling.  The  wrinkles  did 
not,  at  first,  rise  above  the  surface  of  the  sea ;  but 
they  formed  bars  and  shallows,  while  between  them 
were  the  depths.  Over  these  bars  the  tides  and 
waves  stirred  up  sediments  which  settled  in  the 
deeper  water  not  far  remote. 

I  find  no  improbability  in  the  supposition  that 
plant  life  was  now  in  existence.    The  fronds  of  fu- 
coids  could  be  rooted  on  bottoms  within  reach  of  the 
Graphite    aerating  agency  of  the  atmosphere ;  and  though  full 
made  from  sunlight  was  not  yet  revealed  there  was  a  twilight 
remains     sufficient  to  meet  the  requirements  of  the  humblest 
forms  of  vegetal  life.    Whence  this  life  originated, 
science  is  unable  to  declare.    Yesterday  there  was  no 
life  yet,  on  all  the  planet.    To-day  it  is  here — positive 
organic  life.     The   inductive   evidences   supporting 
this  deduction  are  found  in  the  beds  of  graphite  in- 
cluded in  the  older  rocks,  though  I  do  not  imagine 
these  to  have  been  formed  till  many  ages  after  the 
first  advent  of  marine  plants. 

The  time  arrived  when  some  of  the  ever-growing 
wrinkles  rose  dripping  above  the  ocean  level.  They 
were  not,  to  any  great  extent,  domes  and  ridges 
of  granite  and  granitic  rocks.  They  were  arches  of 
the  primeval  fire-formed  crust.  The  mineral  constit- 
uents of  granitoid  rocks  had  indeed  been  formed  as 
already  stated — quartz,  feldspar,  mica  hornblende, 
augite,  and  they  probably  overspread  these  upheav- 


Life 
appears. 


Land 
appears. 


The  War  in  the  Ocean.  276 

als — but  I  believe  these  minerals  must  have  existed 
under  different  aspects,  and  I  think  the  minerals 
which  compose  the  granitoid  rocks  have  resulted 
from  metamorphism  of  plain  sediments,  as  I  shall 
explain.  We  can  not,  therefore,  look  upon  our  oldest 
"  granite  domes"  as  examples  of  the  earliest  crust, 
nor  of  the  earliest  precipitated  beds.  They  are  later. 
Let  us  see. 

There  were  long,  low  ridges  of  barren  rock  now 
emergent.  I  can  not  state  where  they  lay ;  but  it 
seems  probable  they  occupied  nearly  the  places  of 
later  ridges  which  were  to  rise  as  the  germs  of  the 
continents.  Old  ocean  now  seemed  envious  of  his 
loss,  for  he  immediately  began  pounding  and  devour-  ocean 
ing  the  slender  land,  and  taking  it  back  into  his  erosion 
possession.  The  work  of  erosion  was  inaugurated, 
from  which  old  ocean  has  never  desisted  to  this  day. 
Nothing  escaped  from  his  domain  without  a  conflict ; 
and  many  a  patch  of  land  and  many  a  continent  has 
thus  been  reclaimed  for  his  possession,  as  we  shall 
see. 

I  wish  to  emphasize  here  a  doctrine  which  has  been  Sedimen. 
very   generally   overlooked.     Ocean    sedimentation  tation 


has  been  carried  on  only  around  the  continental  . 
slopes.  The  products  of  erosion  have  been  laid  down  coast  line 
in  waters  comparatively  shallow,  and  not  in  the  dis- 
tant abysses  of  the  ocean.  The  deep  remote  sea-bot- 
tom remains  to  our  times,  with  only  a  shallow  cover- 
ing over  the  primitive  crust.  In  our  walk  under  the 
sea,  we  found  no  continental  sediments  in  the  deep 
sea.  We  found  there  a  state  of  changelessness  and 
stagnation.  We  found  no  evidence  of  fragmental 
rocks.  We  found,  on  the  contrary,  in  the  abyssal 


276      Walks  and  Talks  in  the  Geological  Meld. 

islands,  rocks  of  igneous  origin— samples  of  the  old 
fire-formed  crust,  as  I  suspect. 

and  the  The  accumulation  of  sediments  over  any  portion  of 
crust  Ss tbe  ocean'8  bed  would  constitute  a  thickening  of  the 
to  fusion  crust.  But  the  thickness  of  the  crust  was  already 
°er  adjusted  to  the  intensity  of  the  heat  within.  It  was 
of  such  thickness  that  the  heat  within  could  not 
escape  with  rapidity  sufficient  to  melt  the  lower  sur- 
face, and  thin  the  crust.  It  was  of  such  thinness 
that  the  internal  heat  escaped  with  rapidity  suffi- 
cient to  prevent  a  lowering  of  the  temperature  of  the 
different  zones  of  crust,  and  thus  produce  a  thicken- 
ing of  the  crust.  But,  if  by  sedimentation  the  crust 
were  made  thicker,  this  balance  would  be  destroyed  ; 
the  escape  of  internal  heat  would  be  retarded,  and  it 
would  therefore,  re-fuse  the  inner  surface  of  the  crust, 
and  restore  the  thickness,  and  with  it,  the  balance  of 
actions.  Thus,  wherever  the  original  crust  has  been 
supplemented  by  sediments,  more  or  less  of  the  orig- 
inal crust  has  been  lost  from  the  under  side.  Who 
can  say  how  much  has  been  lost  ?  Undoubtedly,  an 
amount  approximating  the  entire  thickness  of  the 
overlying  sediments.  It  is  generally  admitted  that 
the  Eozoic  strata  are  50,000  feet  thick.  There  must 
have  been,  consequently,  50,000  feet  of  the  primitive 
crust  melted  away.  This  leaves  crust  thickening 
due  to  progressive  cooling,  to  be  supplied  by  sedi- 
ments above  the  Eozoic.  If  the  Eozoic  beds  extend 
down  30  miles,  then  30  miles  of  primitive  crust  are 
lost.  If  that  crust  was  less  than  thirty  miles  thick, 
then  some  part  of  the  30  miles  melted  away  must 
have  been  sedimentary  rocks. 
I  wish  to  make  one  more  point  in  this  connection, 


The  War  in  the  Ocean.  277 

and  that,  I  believe,  is  new.     If  sediments  accumu-  sediments 
lated  only  along  the  continental  slopes,  then  not  only  thin  out 
did  all  formations  grow  finer  and  thinner  in  reced- 
ing from  the  shore,  but  they  must  be  found  to  dis- 
appear at  great  distances  from  the  shore — except  in 
shallow  water.    Thus,  we  are  not  at  liberty  to  sup-  Eozoic 
pose  the  Eozoic  beds  extended  under  all  the  oceans,  beds  dld 
so  as  to  be  literally  universal.    Wherever  they  now  tend  un. 
exist,  the  land  was  then  not  far  distant.    Thus  also,  der  a11 
in  general,  it  should  result  that  all  formations  grow 
thinner  and  less  fragmental  as  they  pass  under  newer 
formations. 

So  it  appears  that  by  due  reflection,  it  becomes 
possible  to  reproduce  the  important  features  of  the 
ocean's  primitive  history.  The  earliest  outcrops  of 
sea-bottom  were  entirely  consumed  by  erosion.  We 
find  traces  of  those  lost  lands  in  the  grains  of  vit- 
reous quartz,  which  must  have  been  a  product  of  early 
precipitation.  We  find  other  traces  in  the  conglom- 
erates embraced  in  the  old  Eozoic  rocks.  We  even 
find  traces  in  the  slaty  character  of  many  of  the  peb- 
bles, since  much  alumina  and  silicate  of  alumina 
must  have  been  liberated  in  the  progress  of  the  chem- 
ical conflict,  as  already  explained.  So  when,  at  the 
end  of  the  Eozoic  JSon,  vast  beds  were  upraised 
which  stand  to  our  times,  they  were  not  the  first 
land,  but  only  the  first  land  which  has  survived 
to  the  human  era. 


278     Walks  and  Talks  in  the  Geological  Field. 


XL.     THE  WOULD  WITHOUT  A  BACKBONE. 

REIGN  OF   INVERTEBRATES. 

TheEozoic  UPLIFT,  erosion,  sedimentation,  are  the  key-words 
world.  to  the  physical  history  of  the  world ;  and  these  all 
express  mere  sequences  of  a  more  fundamental  action, 
COOLING.  We  are  now  contemplating  the  world  as  it 
existed  during  the  seon  designated  Eozoic.  Even 
then  some  areas  of  sea-bottom  had  been  upraised 
to  serve  as  sources  for  the  clearly  fragmental  mate- 
rials laid  down  to  become  Eozoic  rocks.  Where  those 
crumbling  lands  were  located,  we  can  not  well  con- 
jecture. It  was  a  reign  of  the  physical  forces  alone. 
The  wide  sea  was  without  a  tenant,  there  were  no 
bleached  shells  strewn  along  the  beach.  No  shrub 
contended  with  the  surf  for  the  possession  of  the 
sandy  foothold ;  and  no  tree,  however  humble,  held 
safer  possession  of  the  sparse  soil  gathered  in  the 
chinks  of  the  knotted  cliffs.  There  was  no  form 
of  living  creature  seeking  the  ends  of  its  being  over 
all  the  stretch  of  the  herbless  land,  and  no  wing 
of  bird  or  insect  agitated  the  fervid  air.  It  was  in 
the  progress  of  this  reign  of  physical  forces  that  I  ex- 
pressed the  opinion  that  vegetal  life  may  have  made 
its  advent  in  the  sea. 

The  seons  of  the  earth's  infancy  rolled  on  ;  the  first 
low  presages  of  coming  continents  had  been  ground 
to  sediment ;  the  only  upraised  examples  of  the 
primitive  chemical  precipitates  had  been  broken  up 
and  returned  to  the  sea.  Over  the  ocean's  floor  was 


How  the 
Eozoic 
rocks- 
granites, 
gneiss, 
etc.— were 
made. 


The  World  ivithout  a  Backbone.  279 

accumulating  a  mud  which,  in  a  later  age,  should  be 
baked  to  granite  and  gneiss— those  granites  and 
gneisses  which  in  our  times,  have  become  forms 
so  familiar.  We  have  before  us  the  evidence  that 
at  least  fifty  to  a  hundred  thousand  feet  of  such  sedi- 
ments accumulated.  The  sea-bottom  bent  down 
under  its  load.  The  downward  protuberance  reached 
into  an  intenser  heat  than  could  be  endured.  Besides 
that,  the  very  thickening  of  the  crust  permitted  the 
interior  heat  to  make  encroachments  upward,  as 
already  explained.  The  water  which  saturated  the 
strata  of  simple  fragmental  sediments  became  in- 
tensely heated  under  a  high  pressure.  Alkaline  sub- 
stances were  dissolved  by  the  heated  water,  and  the 
hot  alkaline  solution  acted  powerfully  on  the  rock- 
materials.  They  were  partly  dissolved — even  silica 
was  dissolved  ;  they  were  partly  softened  ;  they  were 
brought  to  such  a  state  that  the  atoms  were  free  to 
arrange  themselves  according  to  their  affinities  in 
their  new  situation.  The  old  substances  were  there- 
fore made  over  into  minerals  which  did  not  exist 
in  the  sediments  before.  These  minerals  were  formed 
in  juxtaposition  to  each  other  ;  and  when,  in  a  later 
age,  the  temperature  subsided,  the  mineral  mixtures 
which  constitute  Eozoic  rocks  of  the  various  kinds 
were  at  hand.  They  formed  granites,  syenites,  dio- 
rites,  and  similar  rocks,  in  which  the  metamorphosis 
was  so  complete  that  the  lines  of  original  bedding 
were  obliterated.  They  formed  gneisses  and  schists 
in  which  the  metamorphism  was  less  complete. 

The  end  of  the  Eozoic  JEon  approached  at  last.  LJfe  of  the 
Life  had  appeared  in  the  form  of  humble  seaweeds  ;  Eozoic  sea. 
and  life  had  throbbed  into  conscious  being  in  the 


280     Walks  and  Talks  in  the  Geological  Meld. 

forms  of  the  humble  Eozoon  which  I  have  before 
described.  I  can  not  admit  that  no  other  forms  of 
life  found  fitting  home  in  the  Eozoic  sea  ;  but  no 
demonstration  of  it  has  been  discovered.  We  know, : 
however,  that  a  vast  thickness  of  rock-sediment  was 
accumulated,  and  that  now  very  considerable  areas 
were  upraised  to  constitute  the  beginnings  of  those 
Theconti-  lands  destined  to  endure  to  our  time.  Very  likely 
nent  of  the  upheaval  was  accomplished  through  many  partial 
America  uPneavals  widely  separated  in  time.  But  we  can 
begun.  only  contemplate  the  total  result.  When  the  Eozoic 
JEon  was  ended,  and  the  Palaeozoic  JEon  begun,  there 
existed  on  the  American  side  of  the  world,  the  fol- 
lowing outcrops:  1.  The  Great  Northern  Land, 
lying  north  of  the  St.  Lawrence  and  the  Great 
Lakes,  stretching  in  one  direction  to  the  coast  of 
Labrador,  and  in  the  other,  over  the  region  between 
Hudson's  Bay  and  the  Mackenzie  River  to  the  Arctic 
Ocean.  This  sent  a  tongue  across  the  St.  Lawrence, 
at  the  Thousand  Islands,  and  extended  into  the 
Adirondack  Highlands.  2.  The  Seaboard  Land, 
lying  east  of  the  present  Appalachians,  and  reaching 
on  the  north  to  New  England  and  on  the  south  to 
Alabama.  3.  The  Cordilleran  Land,  covering  a  large 
part  of  the  region  west  of  the  Great  Plains — stretch- 
ing from  the  crests  of  the  eastern  ranges  of  the  Rocky 
Mountains  into  California.  Of  its  northern  and 
southern  extent  we  remain  in  ignorance.  Possibly 
this  Cordilleran  Land  was  more  of  the  nature  of  an 
archipelago  than  a  continent.  There  were  smaller  ex- 
posures of  land,  but  we  need  not  speak  of  them  par- 
ticularly. The  rocks  forming  these  continental  nuclei 
are  all  metamorphic.  Between  them  and  the  rocks 


The  World  without  a  Backbone.  281 

immediately  overlying  is  an  abrupt  contrast.  Why 
the  process  of  metamorphism  has  been  thus  limited 
upward,  has  not  yet  been  explained. 

These  lands  were  outstanding  at  the  beginning  of  Some  of 
the  Palaeozoic  JEon.    All  else  was  sea.    I  am  quite  the  lands 
ready  to  believe,  however,  that  other  lands  existed,  have  dis. 
since  consumed  by  the  erosions  which  sought  to  lay  appeared. 
the   foundations  of  newer  formations.     On   the  re- 
moter side  of  this  upheaval  was  an  ocean  barren, 
if  we  can  believe  it,  of  all  forms  of  animal  life.    On 
this  side  was  an  ocean  which  suddenly  teemed  with 
the  shapes  of  sensitive    creatures    already    of  high 
rank,  and  diversified  in    nature,   but    strange   and 
archaic  in  their  structures  and  aspects.    This  sudden  Did  the 
advent   of  hordes  of  creatures  of  diversified  types  Cambrian 

fuuiui  ap- 

of  life  has  been  relied  on  as  evidence  that  the  Cam-  pear  sud- 


brian  fauna  did  not  originate  by  descent  from  any 
older  fauna.  But  you  will  easily  infer  that  I  take 
another  view  of  the  facts. 

Let  us  glance  over  these  populations.    There  are  Life  of 
first  in  order  and  highest  of  all,  the  Trilobites,  which  the  Cam- 
I  have  already  described.     With  them,  in  the  very  brian' 
dawn  of  this  JEoa.  were  Brachiopods  —  few  and  feeble, 
but  in  Lingula  as  strong  and  numerous  as  in  any 
later  age.    Here  grew  also,  calcareous  sponges  —  not 
corals,  but  forerunners  of  corals  —  not  plants,  though 
rooted    and   fixed  —  poor,  humble    creatures   pinned 
helplessly  to  the  sea-mud,  appointed  to  an  age  when 
the  work  of  nature  was  still  crude  and  unfinished,  yet 
sensitive,  capable,  undoubtedly,  of  suffering,  and  capa- 
ble of  enjoying  life.    Death,  certainly,  was  there,  and 
pain.     The  Trilobite,  in  the  very  attitude  in  which 
existence    ended,    reveals    conscious    suffering    and 


282      Walks  and  Talks  in  the  Geological  Field. 

apprehension.  We  often  find  their  forms  closely 
rolled  together,  as  if  shrinking  from  the  felt  ap- 
proach of  death.  The  little  trilobite,  in  his  final 
repose,  proclaims  suffering  and  death  in  the  world 
before  "  sin  entered." 

Life  of  the  Glancing  down  to  the  next  epoch,  we  find  other 
Silurian,  creatures.  Ah,  this  glance  overleaps"  a  million  years 
or  more.  It  is  an  easy  step  for  thought,  but  who  can 
realize  the  slow  rolling  years?  Here  are  trilobites 
still,  and  brachiopods  and  sponges ;  and  here  are 
those  huge  orthoceratites  of  which  I  spoke — long  and 
slimy  tentacles  projecting  at  the  open  end ;  fierce, 
huge  eyes  looking  out  for  some  other  creature  on 
which  to  feed ;  strong,  lance-shaped  teeth  with 
which  to  seize  and  tear  him.  From  this  grim  pres- 
ence all  other  creatures  fled  away — save  those,  alas, 
which  nature  fixed  in  the  soil  and  doomed  to  serve  as 
food  for  these  monster  mollusks.  Here  were  meadows 
of  crinoidal  forms  which  have  already  been  de- 
scribed. Raising  their  sculptured  urns  on  gently 
waving  stems,  they  spread  their  jointed  arms  and 
fingers  in  search  of  their  own  aliment,  and  were 
nipped  for  supper  by  some  ravaging  Orthoceras. 
Here  were  banks  of  polyp  corals — each  little  creature 
planted  in  his  cup  and  expanding  his  petal-like 
tentacles  in  the  life-giving  sunlight.  Over  this  slope 
of  animated  stone  crawled  lazy  sea-snails  grazing  on 
the  tentacled  growths  then  beginning  a  work  of 
coral-building  which  the  Florida  reefs  witness  still  in 
progress. 

The  cycles  of  Cambrian  and  Silurian  time  swept 
on  and  came  to  an  end.  The  history  of  life  showed 
no  departure  from  the  fundamental  types  with 


The  Dynasty  of  Fishes.  283 

which  that  history  was  inaugurated.  There  were 
new  species,  new  genera,  some  new  families,  scarcely 
a  new  order  or  class.  The  changes  were  so  slow  that 
the  world  seemed  finished,  and  finished  for  these 
happy  creatures  that  held  possession  of  it.  Yet  an  changes 
occasional  visitor  from  another  world  would  have 
noted  changes.  The  Cordilleran  Land  had  sunken 


step  by  step,  and  was  even  now  reduced  to  an  archi-  Cambrian 
pelago.  The  Great  Northern  Land,  on  the  contrary,  iurian." 
had  risen  step  by  step,  till  its  southern  limits  ex- 
tended from  Albany  to  Syracuse  and  Buffalo,  and 
thence  to  Detroit,  Mackinac,  Milwaukee,  and  Chi- 
cago. North  of  this  line  lay  the  continental  surface. 
A  great  island  stretched  perhaps,  from  Sandusky  to 
central  Kentucky.  These  lands  were  the  empire  of 
silence  and  desolation.  Populous  as  were  the  waters, 
here  was  no  motion  or  sound  of  animated  creature. 
Sparse,  dwarf  tree-growths  fringed  the  bleak  hori- 
zon, but  flower  and  fruit,  grass  and  herb,  were  yet 
unknown.  The  sea,  always  jealous  of  the  conquests 
made  from  his  domain,  continued  to  growl  around 
the  borders  of  the  land,  and  pursued  industriously 
the  work  of  reclamation  of  his  ancient  slime. 


XLI.     THE  DYNASTY  OF  FISHES. 

DEVONIAN  AND    CARBONIFEROUS    TIMES. 

WHEN  the  morning  of  the  Devonian  Age  dawned,  yerte. 
a  new  form  was  seen  moving  in  the  populous  sea.  bratelife 
It  was  a  vertebrate  form.    Without  a  bony  skeleton, 
its  cartilaginous  framework   and  general  plan   em- 
bodied a  new  conception.    Among  vertebrates  its  or- 


284     Walks  and  Talks  in  the  Geological  Meld. 


Three 
types  of 
Devonian 
fishes. 


ganization  was  decidedly  low  ;  but  it  was  not  a  fish 
in  any  ordinary  acceptation  of  the  term,  though  we 
shall  have  to  call  it  a  fish.  There  were  other  ver- 
tebrate forms  more  clearly  fish-like,  but  all  widely 
separated  from  modern  fishes.  One  could  easily  dis- 
tinguish three  types  of  these  archaic  vertebrates. 
They  are  known  among  us  as  E-las'-wio-branchs, 
Plac'-o-derms,  and  Gan'-oids.  The  Elasmobranchs 
are  a  group  which  still  survives.  They  are  all  shark- 
like.  The  kinds  which  lived  in  the  Devonian  were 
true  sharks  (Sel'-a-choids)  of  the  peculiar  Ces-trac'*i-on 
.  family,  the  best  known  species  of  which  ranges  from 
Elasmo-  JaPan  to  ^"ew  Zealand.  Cestracion,  the  Port  Jack- 
.branchs.  son  Shark,  has  spines  in  front  of  both  the  dorsal  fins  ; 
the  nostrils  unite  in  the  cavity  of  the  mouth,  and 
the  upper  lip  is  divided  into  seven  lobes.  The  teeth 
along  the  middle  of  the  mouth  are  small.  External 
to  these  are  large  flat  teeth  twice  as  broad  as  long, 
arranged  in  oblique  series  so  as  to  form  a  sort  of  tes- 
selated  crushing  surface. 

Among  the  very  earliest  American  fishes  were 
some  of  these  spine-bearing  sharks.  The  spines  are 
flattened,  two-edged  like  a  bayonet,  and  curved  as 
if  one  had  belonged  to  the  right  side  and  the  other 
to  the  left.  The  external  surface  was  covered  with 
a  thin  coating  of  enamel,  sometimes  smooth,  some- 
times ornamented.  These  spines  are  not  attached  by 
a  joint,  but  inserted  in  a  mass  of  cartilage  imbedded 
in  the  flesh.  They  were  perhaps  the  front  rays  of 
the  pectoral  fins.  Some  of  them  were  more  than  a 
foot  in  length.  Being  two-edged  and  very  sharp, 
they  must  have  been  very  powerful  weapons,  offen- 
sive or  defensive.  These  cestracionts  were  numerous 


The  Dynasty  of  Fishes.  285 

during  the  Corniferous  period.  Their  smooth,  brown 
spines  are  very  often  found  in  the  Corniferous  Lime- 
stone of  New  York,  Canada,  Ohio  and  Michigan.  If 
you  wish  the  name,  here  it  is:  " Machcer"-a-can'- 
tfms"or  "Dagger-spine." 

Another  type  among  the  earliest  American  fishes  Plated 
was  (Rhyn'-cho-dus  or  "Beak-tooth")  a  form  related  Ganoids, 
to  the  Chi-mce'-ra,  which  also  resembles  sharks.  It 
has,  however,  a  long,  whip-like  tail ;  its  gill-slits  are 
covered  by  a  flap  of  skin,  and  the  skull  is  blended 
with  the  jaws.  The  teeth  consist  of  minute  denti- 
cles firmly  massed  together  into  large  tabular  plates 
which  are  inseparably  blended  with  the  jaws.  It 
has  a  long  and  powerful  spine  in  front  of  each  dor- 
sal fin.  The  only  known  specimens  of  Rhyn'chodus 
are  found  in  the  Corniferous  Limestone  of  Ohio  ; 
but  it  must  have  had  a  much  wider  range. 

Another  of  the  most  common  and  most  striking 
fishes  of  the  same  age  appears  to  have  been  a  rela- 
tive of  the  modern  sturgeons  —  a  family  of  plated 
Ganoids.  Our  American  geologists  have  almost 
buried  it  under  a  pile  of  nomenclature,  which  they 
have  finished  in  the  following  shape :  Mac-ro-pet- 
al-ich'-thys  or  "  Big-plated  fish."  These  fishes  were 
of  large  size.  The  cranium  was  composed  of  large 
polygonal  plates,  united  by  double  sutures  which  are 
nearly  concealed  by  the  tubercled  enameled  surface  ; 
the  tubercles  are  stellate  ;  the  surface  is  ornamented 
by  double  rows  of  pores  and  single  thread  lines,  form- 
ing a  pattern  which  does  not  correspond  with  the 
plates  below.  These  large,  geometrically  formed 
plates  often  attract  the  attention  of  quarrymen,  since 
they  are  sometimes  fifteen  inches  in  length. 


286      Walks  and  Talks  in  the  Geological  Field. 

Ganoids.  In  this  assemblage  of  old  American  fishes,  we  have 
to  mention  one  more.  This  is  a  ganoid  by  the  name 
of  O-nych'-o-dus  or  "Hook-tooth."  It  was  of  large 
size.  The  cranium  was  composed  of  a  large  number 
of  bony  plates  covered  with  an  enameled  and  tuber- 
cled  surface.  The  borders  of  the  jaws  were  set  with 
a  row  of  conical,  acute,  more  or  less  recurved,  teeth  ; 
and,  in  the  middle  of  the  lower  jaw  in  front,  was  a 
single  series  of  large,  curved,  conical  teeth,  present- 
ing a  striking  appearance,  and  often  found  imbedded 
in  the  Corniferous  Limestone.  The  body  of  the  fish 
was  covered  with  rounded,  overlapping,  bony  scales, 
nearly  circular  in  outline,  and  about  an  inch  in  di- 
ameter. 

Please  notice  that  these  old  American  fishes,  dating 
from  the  Corniferous  period,  are  Elasmobranchs  and 
Ganoids.  Of  the  former,  there  were  two  types,  Ces- 
tracionts  and  Chimaeroids.  Of  the  latter,  also  two 
types — related  to  sturgeons  and  gar-pikes. 

First  fishes     *n  *ne  Upper  Ludlow  rocks  of   England,  which 

Silurian,  form  the  upper  part  of  the  Silurian,  is  a  "  bone-bed  " 
composed  almost  entirely  of  the  remains  of  fishes, 
much  triturated  and  matted  together.  From  this 
bed  spines  of  On'-chus  have  been  obtained— a  fish 
apparently  belonging  to  the  Cestraciont  type  of 

„  sharks.    In  the  Upper  Ludlow  have  been  found,  also, 

portions  of  Ceph-al-as^is,  or  "  Shield-head,"  having 
the  head  covered  by  a  broad  plate.  This  fish  was  in- 
termediate between  Placoderms  and  Ganoids.  Still 
lower  down  in  the  "  Lower  Ludlow,"  relics  of  a  sim- 
ilar fish  called  Pter-as'-pis  or  "Wing-shield"  have 
been  found.  So  we  say  the  oldest  fishes  of  Great 
Britain  lived  in  the  Silurian  Age.  We  know  also, 


The  Dynasty  of  Fishes.  287 

that  very  similar  fishes  dwelt  contemporaneously  in 
the  waters  which  covered  Russia  and  Bohemia. 

I  have  next  to  inform  you  that  this  record  is  beaten  America 
hy  America.  It  has  very  recently  been  announced 
by  Professor  Claypole  that  the  Corniferous  Period 
was  not  the  earliest  date  of  American  fishes.  He 
finds  remains  of  fishes  in  the  lower  and  upper  portions 
of  the,  Salina  Group  of  Pennsylvania.  They  appear 
to  be  related  to  Placoderms  and  Ganoids,  and  he  has 
bestowed  on  them  the  name  Pal-ce-as'pis  or  "Ancient 
Shield."  Still  lower  than  this  he  reports  some  fish 
remains  which  he  thinks  may  be  referred  to  the  genus 
On'-chus.  These  are  at  the  bottom  of  the  Clinton 
Group,  which  in  Pennsylvania  is  fifteen  hundred  feet 
below  the  Corniferous  Limestone,  and  is  two  for- 
mations lower  than  the  oldest  fish  remains  of  Europe. 

We  have  now  stirred  up  all  the  old  bones  —  the  old- 


est  bones  buried  on  our  planet  —  so  far  as  we  know.  were  the 
But  I  do  not  think  we  have  found  the  first  fishes  yet.  of  these 
There  must  have  been  some  forms  still  less  like  fishes  fishes? 
than  these.  Perhaps  if  we  could  carry  the  line  back, 
we  should  find  fish-like  creatures  approximating 
more  and  more  to  crustacean  creatures.  There  was 
Pter-y-go'-tus  in  the  Old  World  and  America,  and 
Eu-^ryp'-te^rus  plentiful  in  America,  with  its  ex- 
tended pair  of  arms  reminding  one  forcibly  of  the 
Ptewch'-thys  or  "Winged-fish"  of  the  Old  Red 
Sandstone.  There  was  Cephalaspis,  with  its  broad 
head-shield  exceedingly  similar  to  the  shield  of  the 
modern  King  Crab  and  some  of  the  old  trilobites. 
Other  intimations  exist  of  a  possible  near  relation- 
ship between  these  half  completed  vertebrates  and 
the  dying-out  forms  of  Crustaceans. 


288      Walks  and  Talks  in  the  Geological  Field. 

The  later  These  relations  enable  us  to  contemplate  with  new 
history  of  interest,  some  of  the  despised  fishes  which  live  in 
fish'types.  our  times.  Our  sturgeons,  gar-pikes,  and  sharks  are 
the  sparse  representatives  of  those  ancient  families 
which  once  sustained  alone,  the  dignity  of  the  ver- 
tebrate type.  Of  these  ancient  families,  the  placo- 
derm  was  destined  to  disappear  with  the  Devonian, 
and  without  a  successor.  The  sturgeon-type  has  sur- 
vived in  a  slender  line  of  representatives,  to  the  hu- 
man epoch.  The  cestraciont  sharks  were  probably 
differentiated  into  the  various  better  known  families 
of  modern  sharks,  but  continue  to  our  times,  to  ex- 
emplify the  probable  nature  of  old  Onchus,  patriarch 
of  sharks.  The  bony  scaled  ganoids — more  fish-like 
than  any  of  the  others,  both  in  form  and  scaly  cov- 
ering— were  well  represented  by  Onych'odus.  The 
power  and  numbers  of  their  family  continued  to  in- 
crease through  Carboniferous  and  Mesozoic  times ; 
but  then  they  dwindled  away.  In  modern  times, 
our  familiar  bony-scaled  gar-pike  haunts  the  fresh- 
ened waters  of  river  and  lake — the  poor  degenerate 
descendant  of  ancestors  which  once  dominated  over 
the  world.  Venerable  relic  of  a  mighty  empire  ! 
The  lesson  Why  have  these  creatures  been  preserved  in  exist- 

of  the  gar-  ence  so  iong?     These  forms  are  misplaced  in  the 
pike,  stur- 
geon, and  modern  world.    They    constitute    an    anachronism, 

shark.  which  is  either  an  absurdity,  or  a  phenomenon  too 
full  of  meaning  for  ordinary  comprehension.  The 
gar-pike  destroys  our  game-fish  and  our  market-fish 
— as  he  ravaged  neighboring  kingdoms  while  he  ruled 
an  empire  of  his  own.  He  tangles  and  tears  the 
nets  of  the  fishermen,  who  visit  their  execrations 
upon  him.  His  flesh  is  unpalatable  for  food.  The 


The  Dynasty  of  Fishes. 


mud-loving  sturgeon,  less  destructive  in  his  na- 
ture, brings  no  utility  into  the  modern  world.  The 
fierce  shark,  equally  unfit  for  food,  is  the  freebooter 
of  the  ocean.  Other  fishes  furnish  aliment  to  man. 
But  these  archaic  types  linger  from  a  time  when  hu- 
man wants  had  as  yet  no  existence,  when  human 
food  was  not  demanded.  They  were  never  in- 
tended for  food,  since  they  made  food  of  every  other 
creature.  These  useless  and  destructive  beings  are 
out  of  joint  with  the  world  and  with  history.  Why 
are  they  here  ? 

Why?  They  come  to  import  ideas  into  the  modern 
world.  They  bring  down  to  us  living  illustrations  of 
faunas  passed  away.  The  plates  of  Cephalaspis  and 
the  spines  of  Machceracanthus  quarried  from  the  rock 
might  pique  our  curiosity  and  distress  us  by  their 
mystery  ;  but  they  would  not  instruct.  It  was  in- 
tended that  the  intelligence  of  the  being  which 
always  stood  as  the  finality  of  organic  improvement 
should  grasp  the  conception  of  the  world,  and  repro- 
duce the  grand  history  of  departed  cycles.  Why? 
It  was  an  act  of  beneficence  which  saved  these  relics 
of  ancient  dynasties  from  total  destruction.  There 
was  purpose,  not  accident,  in  the  failure  of  their  com- 
plete extinction,  and  the  assignment  of  the  world  ex- 
clusively to  more  modern  creatures.  These  are  pre- 
cious examples  preserved  in  a  museum.  These  are 
caskets  filled  with  documents  from  an  olden  time. 
The  gar-pike  and  the  sturgeon  and  the  shark  are 
missionaries  from  the  past  to  the  present.  Hear 
them.  They  are  preaching  to  man's  intelligence. 
They  are  unfolding  the  plans  of  Infinite  Wisdom. 
"  He  that  hath  ears  to  hear,  let  him  hear." 


290     Walks  and  Talks  in  the  Geological  Meld. 


XML     SCENES  FROM  THE  COAL  PERIOD. 

HOW  THE  COAL  BEDS  WERE  FORMED. 

A  new  age  WHILE  the  monsters  of  the  ancient  deep  were 
dawns.  luxuriating  in  empire  and  blood,  the  premonitions  of 
progress  were  felt.  Behold,  the  tide  bears  out  into 
the  sea  a  floating  log.  Its  exterior  is  marked  by 
peculiar  and  significant  impressions.  They  reveal  the 
crest  of  a  dynasty  in  the  vegetal  world.  They  are  the 
seal  of  a  Sigilla'ria,  or  the  scars  of  a  Lepidoden'dron. 
It  has  floated  from  the  shore  of  a  low-lying  and  silent 
continent. 

It  was  the  beginning  of  the  Carboniferous  Age. 
h®  tremors  incident  to  the  upthrow  of  a  new  belt 
of  land  had  strewn  the  submerged  continental  slope 
with  the  sandy  ruins  of  older  lands,  and  left  the  bed 
to  mark  the  beginning  of  a  new  system  of  strata. 
We  know  these  hardened  sands  as  Waverly  Sand- 
stone and  Marshall  Sandstone.    They  were  not  out- 
spread in  a  day.    Through  another  age  still,  the  im- 
pending events,  heralded  by  the  floating  log,  were 
Abundant  destined  to  be  delayed.    Meantime  the  waters  deep- 
sea  life.      ene(jj  an(j  nature  seemed  to  have  forgotten  her  an- 
nouncement.    She   had    promised    land  and  green 
forests ;  she  gave  deep  sea  and  an  expansion  of  the 
empire  of  bony-scaled  ganoids.     She  gave  larger  de- 
Brach-        velopment    to    Brach/iopods  ;  she  dallied  with    the 
iopods.       chambered  shells,  and  gave  the  world  an  improved 
Ooni          *vPe»  wh-ich    we  have  named    Go-ni-a-ti'-tes.     She 
tites.  lingered  lovingly  over  one  of  her  ancient  conceptions 


Scenes  from  the  Coal  Period.  291 

which  we  style  crinoidal.  She  had  had  it  in  her 
repertory  of  beautiful  thoughts  since  early  Cambrian 
times— the  pretty  little  stone  lily.  She  had  taken 
it  up  in  every  age,  and  had  turned  off  some  improve- 
ments and  some  new  decorations.  But  now,  during 
this  waiting  period,  she  seems  to  have  returned  with 
true  devotion  to  one  of  her  first  ideas.  She  gave  crinoids. 
great  attention  to  diversifying  it,  decorating  it,  and 
filling  the  sea  with  its  delicate  and  graceful  forms. 
All  for  the  Age — not  for  perpetuity. 

This  dream  of  placid  waters  and  teeming  popula- 
tions was  broken  by  a  jar.  Some  stay  of  the  long 
pressed  crust  of  the  earth  was  broken  by  the  accumu- 
lated strain,  and  the  mud  of  the  sea  was  stirred  from 
its  prolonged  repose,  and  floated  over  the  fields  where 
stone-lilies  had  flourished,  generation  after  genera- 
tion. Tenants  of  the  sea  alarmed,  retreated  to  deeper 
waters  or  perished  in  their  homes,  and  received  a 
Pompeiian  burial.  The  ocean-bottom  had  been  lifted 
to  a  higher  level.  The  scene  was  totally  changed. 

The  summer  sea  became  a  stormy  and  turbid  shore  ;  „ 

Growth  of 

and  a  broad  belt  was  given  to  the  land.    The  torn  the  conti- 
beach,    crumbling    before   the   waves,    contributed  nent> 
coarse  rubble  for  the  foundations  of  new  land  in  some 
future  age.    The  vegetation  promised  for  the  impend- 
ing   epoch    was    crowding    into    possession    of  the 
ground.    It  flung  its  fragments  into  the  deep.    These 
chips  from  the  by-standing  forest  were  buried  in  the 
sands  which  loaded  the  sea-bottom. 

Now  came  the  first  charge  in  the  conflict  destined 
to  alternate  during  an  age  ;  another  collapse  of  some 
of  the  stays  and  supports  of  the  rigid  crust.  The 
land  uprose  by  another  notcli  ;  the  bottom  of  the  sea 


292      Walks  and  Talks  in  the  Geological  field. 

was  lifted  to  the  surface.  The  great  "  Carboniferous 
Conglomerate  "  was  now  first  bathed  in  air  and  sun- 
light. The  continent  of  North  America  received 
an  annexation  of  territory  which  stretched  from  the 
Seaboard  Land  east  of  the  Appalachians,  to  the 
Great  Plains.  The  new  territory  included  all  the 
regions  which  had  been  selected  as  the  sites  of  the 
capacious  coal  repositories,  for  the  use  of  civilization. 
Great  ^  was  no*  a  dry  upland.  It  was  a  broad  and  mighty 
swamps  marsh.  Michigan  was  not  included  in  the  common 
continental  marsh,  but  stood  apart  for  a  special 
destiny. 

A  forest  Now,  over  all  this  breadth  of  bog  and  swale  sprang 
arises*1  u^  veSetable  growths — trees  and  herbs,  ferns  and 
rushes.  Whence  these  forms  ?  Some,  as  I  said,  had 
been  nursed  on  the  older  and  contiguous  land,  and 
now  entered  upon  a  new  possession  because  it  was 
fit.  Some  sprang  from,  germs  fresh  planted  by 
some  unseen  hand.  What  mean  all  these  transfor- 
mations? This  luxuriant  crop  is  sustained  by  the 
carbonic  acid  of  the  atmosphere.  This,  as  is  generally 
supposed,  was  in  excess.  It  made  the  air  irrespirable; 
no  terrestrial  creature  could  live.  But  terrestrial 
animals  must  constitute  the  next  step  of  progress. 
The  march  of  improvement  had  now  gone  as  far  as 
possible  with  water-breathing  populations.  The 
highest  type  of  animals  had  been  reached  and  its 
aquatic  class  had  lived  a  striking  career.  Nature  had 
now  paused  for  the  purification  of  the  air  for  the 
next  class. 

Theatmos-  The  Power  which  had  called  matter  and  force  into 
of  carbon-  existence,  could  have  made  other  disposition  of  this 
icacid.  difficulty.  The  carbonic  acid  could  have  been  com- 


Scenes  from  the  Coal  Period.  293 

bined  with  lime  and  fixed  in  limestones.  It  could 
have  been  banished  from  the  planet.  But  carbon  is 
precious.  It  is  the  basis  of  all  our  combustion.  It 
warms  and  blazes  in  coal  and  petroleum,  peat  and 
gas.  The  carbon  must  be  preserved  for  future  use. 
Man  would  discover  its  utilities,  though  the  age  then 
passing  had  no  use  for  it.  Man  was  yet  far  off; 
but  man  was  anticipated ;  man  was  involved  in  the 
plans  of  the  world  ;  man  was  prophesied  in  these 
preparations. 

So  vegetation  was  appointed  to  do  the  work  and  In  llfe  the 
conserve  the  material.  This  explains  the  presence  of  vegetation 
coal-making  trees  upon  the  shores  of  the  preceding  the  air 
epoch.  They  came  by  appointment,  they  were  to  ful- 
fill a  plan  ;  they  stood  waiting  by  the  border  of  a 
domain  which  had  been  promised  them  for  a  posses- 
sion. Unlimited  supplies  of  aliment  pervaded  the  at- 
mosphere. The  marshy  situation  exhaled  the  abund- 
ant vapor  in  which  vegetation  delights.  The  earth, 
in  its  comparative  newness,  retained  the  warmth 
to  stimulate  at  the  root.  So  tree-fern  and  herbaceous 
fern,  calamite  and  sigillaria,  begin  work.  Atom 
by  atom,  they  selected  the  poison  from  the  atmos- 
phere, and,  returning  the  oxygen,  fixed  the  carbon  in 
their  tissues.  Frond,  stem,  and  root  treasured  up  the 
fuel  impelled  by  the  force  of  sunlight ;  every  pound 
of  vegetable  answered  to  a  given  amount  of  solar 
force. 

The  work  was  begun.  Generations  of  plants  sue-  and  in 
ceeding  each  other  fell  prostrate  at  last,  and  added  death 
their  substance  to  the  growing  bed  of  peat.  Stand- 
ing  water  protected  the  peat  from  decomposition,  for  the 
Now  the  skies  again  were  lowering  and  forebodings 


294      Walks  and  Talks  in  the  Geological  Meld. 

of  change  trembled  through  the  continent.  A  cat- 
aclysm was  at  hand.  The  wide  expanse  of  marshy 
land  again  went  down.  Old  ocean,  which  had  roared 
and  frothed  in  rage  around  the  borders  of  the  terri- 
tory of  which  he  had  been  dispossessed,  came  career- 
ing back  to  his  old  haunts.  He  brought  a  freight  of 
mud  and  sand,  and  spread  it  over  the  whole  vast 
peat-bed.  Beds  of  clay  and  sand  shut  out  from  the 
atmosphere  the  sheet  of  peaty  matter  which  was  to 
lie  and  consolidate  to  coal. 

Aiterna-        The  dominion  of  the  ocean  was  temporary.    Again 
Bottom"     ^e  reeking  sea-bottom  came  up  to    sunlight,  and 
and  forest  another  scene  of  bright  verdure  was  spread   where 
swamp.      late>  old  ocean  had  celebrated  a  j ubilee.   It  looked  as  if 
the  former  forest  had  undergone  a  resurrection.   Here 
stood  again   Lepidodendron  and  Sigillaria  and  the 
other  established  forms.    But  they  were  other  species; 
and  with  them  was  an  occasional  newcomer  among 
Life  in       the  vegetable  types.     They  resumed  the  work   of 
these         selecting  the  impurity  from  the  air.    Already,  some 
adventurous  and  hardy  types  of  air-breathers  had 
colonized  the  jungle.    They  were  sluggish  and  slimy 
creatures,  with  whom  life  passed  slowly,  and  respira- 
tion was  a  matter  of  comparative  indifference.     Yet 
they  enjoyed  existence.     They  grazed  on  the  humble 
herb  ;  they  seized  the  dragon-fly,  alighted  to  rest  his 
wing ;  they  violated  the  home  retreats  of  the  passive 
snails.     They  crawled  out  and  sunned  themselves 
on  the  ferny  bank.    There  were  grosser  and  heavier 
forms,  mail-clad  and  vociferous ;  haunting  the  bayou  ; 
paddling  for  some  eligible  fishing  station  ;  bellowing 
like  oxen,  when  excited  in  pursuit ;  stirring  up  the 
mire  of  the  stagnant  bay  ;  resting  their  chins  on  the 


Scenes  from    the  Coal  Period.  295 

reeking  bank  to  absorb  the  slanting  sun-warmth 
of  the  early  morning,  or  lolling  under  the  noonday 
shade  of  some  wide-spreading  and  umbrageous  Lepi- 
dodendron. 

At  the  entrance  of  the  bay  was  an  exposed  head-  For- 
land.  From  this  the  high  beach  stretched  away  for 
miles ;  and  already  the  older  coal  deposits  were  ex-  coal, 
posed  along  the  eroded  cliffs.  Here  the  waves 
pounded  up  beds  of  sandstone,  shale,  and  coal.  The 
sands  were  deposited  along  the  beach  which  faced 
the  open  sea.  The  finer  and  lighter  materials  were 
floated  off  in  search  of  a  quieter  nook.  In  the  bay 
they  found  a  retreat  from  wind  and  waves,  and  there 
laid  themselves  down  in  a  mixture  of  comminuted 
coal  and  clay.  In  a  later  age,  the  deposit  was  a  bed 
of  cannel  coal. 

The  land  continued  to  oscillate  as  long  as  the  pu- 
rification of  the  air  was  incomplete.  Again  and 
again,  the  forest  resumed  its  work,  and  bed  after  bed 
was  stored  away  beneath  ocean  sediments,  to  await 
the  end.  When  the  beneficent  work  had  been  ac- 
complished, the  tired  forces,  that  had  endured  with 
trembling  and  vibrations,  the  enormous  strain  that 
had  been  accumulating  under  the  prolonged  contrac- 
tion of  the  interior,  yielded  with  a  tremendous  col- 
lapse which  jarred  the  hemisphere.  Huge  folds  of  The  close 
the  massive  crust  uprose,  and  were  mashed  together 
till  their  crests  pierced  the  clouds.  This  was  the 
birth  of  the  Appalachians.  It  was  the  end  of  the 
long  Palaeozoic  ^Eon.  Only  the  stumps  of  those  folds 
remain  to-day.  Though  crumbling,  they  stand  as 
monuments  of  the  mighty  throes  through  which 
the  world  was  prepared  for  man  and  civilization. 


296      Walks  and  Talks  in  the  Geological  Meld. 


Anew 
world. 


Flora. 


Amphib- 
ians. 


XLIII.     THE  EEPTILE  MONARCHIES. 

MESOZOIC   EVENTS. 

THE  storm  is  cleared,  and  a  new  sky  overhangs 
the  scene.  We  seem,  to  be  in  another  world.  We 
glance  over  the  territory  lately  covered  by  luxuriant 
coal-vegetation,  and  Cycads  and  Voltzias  now  hold 
possession.  The  Cycads  are  palmetto-like  in  form, 
fern-like  in  foliage,  and  pine-like  in  affinities ;  the 
Voltzia  seems  a  progenitor  of  the  cypress.  No  Lep- 
idodendron  or  Sigillaria  raises  its  green  crown  in  all 
the  wooded  landscape.  The  reeking  marsh  has  dis- 
appeared, and  an  undulating  upland  occupies  the 
continent.  We  glance  over  the  place  of  the  great 
flat  which  had  stretched  from  New  England  to  Ala- 
bama, and  dark-wooded  ranges  of  mountains  frown 
down  on  us.  We  search  for  the  old  shore-line  which 
had  set  the  bounds  to  the  empire  of  the  sea,  and  it 
is  removed.  Far  southward  it  lies,  within  two  hun- 
dred miles  of  the  Gulf-border  of  the  human  epoch— 
so  much  more  of  the  ocean's  domain  has  been 
wrested  from  his  possession. 

We  range  over  this  new  bright  landscape.  All  the 
old  Palaeozoic  forms  of  animal  life  are  displaced. 
Strange  tenants  have  moved  in.  Instead  of  the 
feeble,  lizard-shaped  Amphibians  which  housed 
themselves  in  a  hollow  stump,  we  find  great  quad- 
ruped-like Labyrin'thodonts  crawling  like  enormous 
toads  under  shelter  of  a  fringe  of  forest.  Their  pon- 
derous bulk  impresses  deep  footprints  in  the  sand 


The  Reptile  Monarchies.  297 

along  the  beach — four-toed  and  hand-like — destined 
to  remain  and  become  a  wonder  of  the  human  age. 
(See  also  Talk  XXX.) 

But  the  Amphibians  have  yielded  empire  to  an-  Reptiles, 
other  dynasty.  Great  was  Archegosaurus,  but  Deino- 
saur  was  greater.  An  extraordinary  and  amazing  Demo- 
figure  reveals  itself  stalking  along  over  the  beach.  saurs- 
Evidently  this  monster,  tall,  scale-covered,  erect, 
with  diminutive  head,  swollen  abdomen,  and  mas- 
sive, trailing  tail,  is  a  representative  of  the  ruling 
family.  He  reveals  massiveness  without  elegance  ; 
strength,  without  grace.  He  marches  on  two  feet 
and  leaves  a  footprint  three-toed  like  that  of  a  bird. 
His  jaws  are  armed  with  strong,  sharp-edged,  and 
pointed  teeth.  His  long  bones  are  hollow  like  those 
of  birds  ;  the  pelvis,  as  well  as  the  foot,  is  bird-like  ; 
the  sacrum  has  four  vertebrae  like  that  of  a  mammal ; 
the  neck-vertebrse  are  concavo-convex  as  in  mam- 
mals, and  his  lower  jaw  has  lateral  motion  for  tritu- 
rating food,  as  in  the  ox.  Shape  like  a  frog  ;  head, 
tail,  and  scales  like  a  lizard  ;  feet  like  a  bird  ;  sacrum 
like  a  mammal— what  shall  we  call  the  creature  ? 

We  watch  him  through  his  sea-side  promenade, 
and  follow  him  to  the  dank  and  peaty  jungle  where 
he  finds  his  home.  We  see  him  browse  from  the 
lower  tufts  of  foliage,  and  grind  the  fibrous  twigs  with 
the  jaw-movements  of  a  herbivore,  wearing  away 
and  blunting  the  crowns  of  his  teeth.  But  he  meets 
his  enemy— another  Deinosaur  of  bloodthirsty  dispo- 
sition, a  flesh-eater,  and  armed  with  sharp  and  lacer- 
ating teeth.  Between  the  two  a  bitter  feud  exists, 
and  they  have,  at  former  times,  clenched  in  the 
struggle  for  prowess.  The  herbivore  recognizes  his 


298      Walks  and  Talks  in  the  Geological  Meld. 

superior  ;  but  unwillingly  subject,  fierce  anger  flashes 
from,  his  dark  eye,  and  with  a  defiant  growl,  he 
makes  room  for  carnivore  to  pass. 

Sea-  There  are  others  of  the  ruling  dynasty  which  dis- 

saurians.    porfc  themselves  in  the  waves  ;  but  these  sea-saurians 

(Enaliosaurs)  are  only  the  forerunners  of  an  army 

which  may  be  expected  in  the  morning  of  another 

age.    There  are  also  others.    We  walk  in  the  twilight 

of  a  Mesozoic  day,  along  the  reedy  shore  of  a  gloomy 

estuary,  and  the  crocodiles  are  crawling  out  on  the 

Croco        land  for  midnight  prowling.    A  broad  crocodilian 

dilians.      grin  reveajs  an  array  of  cruel,  conical  teeth  set  in  the 

jaws  ;  and  their  lazy  forms  are  encased  in  a  jointed 

bony  cuirass,  which  fits  them  for  defensive  warfare. 

When  Bel'odon  moves  through  the  jungle,  even  the 

Deinosaur  is  startled  from  his  security. 

Estuary  Within  the  limits  of  that  recess  of  the  continent 
of  the"0118  destined  to  be  named  New  England,  is  a  deep  and 
Triassic  narrow  bay,  which  projects  far  northward  from  the 
Period.  future  shore  of  Long  Island  Sound.  We  stand  upon 
the  gneissic  slope  of  the  western  shore,  and  survey  the 
shining  expanse.  The  tide  is  out,  and  the  smooth 
sand  beach  is  laid  bare.  Over  its  surface  lie  squirm- 
ing and  crawling  and  shrinking  from  exposure,  the 
sundry  forms  of  marine  life  which  the  last  tide 
brought  up.  This  is  the  opportunity  for  the  land- 
marauders.  Now  they  hurry  to  the  scene  in  search 
of  a  meal.  There,  most  conspicuously,  strides  the 
tall  uncouth  jBron-to-zo'-um,  a  three-toed  Deinosaur, 
standing  fourteen  feet  high.  Its  foot  is  twenty-four 
inches  long.  At  times  it  drops  011  four  feet  to  seize  a 
dainty  morsel  of  a  crab,  and  leaves,  for  a  space,  the 
footprints  of  a  quadruped.  But  the  forward  feet  are 


The  Reptile  Monarchies.  299 

comparatively  diminutive  in  size.  In  the  distance, 
Oto-zo'-um,  paces  along  the  beach— another  bipedal 
Deinosaur,  but  with  four  toes  behind.  With  foot 
twenty  inches  in  length,  he  has  a  stride  of  three  feet, 
in  a  leisurely  gait.  Otozo'um  is  partaking  of  his 
meal.  Now  and  then  he  picks  up  a  stranded  fish. 
Among  these  gigantic  figures  more  humble  Deino- 
saurs  are  seen  mingling.  One  of  these  leaves  a  foot- 
print but  three  inches  ;  and  we  notice  one  wee  pet  of 
a  reptile  which  makes  a  track  but  a  quarter  of  an 
inch  in  length.  They  are  all  engaged  in  refreshing 
themselves. 

Let  us  wait  here  for  the  tide  to  come  in.  It  is  com-  How  foot_ 
ing,  and  announces  itself  by  its  roar.  The  tide  of  the  prints  in 
open  sea  is  here  augmented  by  the  limits  of  the  nar- 
rowing  bay,  and  it  swells  into  a  terror-striking 
"bore."  The  Deinosaurs  and  Labyrinthodons  hear 
the  sound,  raise  higher  their  heads  in  listening  atti- 
tudes, and  scurry  away  to  their  retreats.  The  tide 
lingers  awhile,  dallying  with  the  sands,  and  then  re- 
tires. Where  now,  are  the  footprints  of  those  gigan- 
tic saurians  ?  Has  the  dallying  tide  erased  them  ? 
No.  It  has  covered  them  with  a  soft  film  of  fine 
sand.  They  are  not  destroyed ;  they  are  preserved. 
The  table  is  spread  again  with  squirming  viands,  and 
the  saurians  recognize  another  call  to  refreshments. 
Again  they  range  along  the  sand,  and  impress  their 
tracks  in  the  soft  surface.  Unconsciously,  these 
creatures  are  inscribing  their  autographs  on  the 
pages  of  the  world's  history.  The  tide  returns  and 
spreads  its  conservative  sands  again  over  the  well- 
inscribed  beaches.  And  so  the  tide  rolls  in  and  out, 
and  the  saurians  write  their  daily  chapters  of  his- 


300     Walks  and  Talks  in  the  Geological  Field. 

tory.  By  and  by  the  tides  will  cease  ;  this  bay  will 
be  uplifted  beyond  their  reach  ;  these  sands  will  be- 
come a  solid  brown  sandstone ;  quarrymen  will  ply 
their  avocation  along  the  slopes  where  Otozo'um 
breakfasted  ;  the  stony  slabs  will  be  split  apart,  and 
there  will  be  found,  in  all  their  details,  the  same  foot- 
prints made  in  this  opening  epoch  of  the  Middle 
Ages  of  the  continent's  history. 

Mesozoic  So  the  years  rolled  on  ;  and  meantime  the  vegeta- 
coal-beds.  ^jg  kingdom  was  performing  its  part  in  the  drama  of 
the  world.  There  must  have  been  lowlands  where 
water-loving  trees  stood  and  bathed  their  feet — 
swamps,  where  fallen  foliage  and  worn-out  tree 
trunks  gathered  themselves  in  beds  of  peat  that 
hardened  into  coal.  One  of  those  tracts  is  a  few 
miles  west  of  Richmond,  Virginia  ;  and  two  others 
are  in  the  Deep  River  and  Dan  River  regions  of 
North  Carolina.  Good  coal  was  formed,  quite  simi- 
lar to  the  bituminous  coal  of  the  Carboniferous  Age. 
Conditions  The  Triassic  Age  came  to  a  close  through  move- 
at  the  close  ments  of  a  nature  similar  to  those  which  closed  the 
Triastic.  Carboniferous,  but  less  pronounced  in  violence.  The 
sandy  beds  were  disturbed  and  tilted,  all  the  way 
from  Nova  Scotia  to  North  Carolina.  The  strains 
which  they  suffered  caused  great  fractures  which  in- 
tersected the  formation  in  straight  lines  ;  and  from 
below  came  molten  mineral  matter  which  filled  the 
fissures.  The  matter  was  of  a  basaltic  character,  and 
in  places  where  it  overflowed  on  an  extensive  scale, 
it  assumed  a  columnar  structure.  We  note  especially 
four  regions  of  Triassic  sandstones  and  Triassic  erup- 
tions :  Western  Nova  Scotia,  the  Connecticut  Val- 
ley, the  Palisade  region,  extending  through  New 


The  Reptile  Monarchies.  301 

Jersey  and  Pennsylvania,  four  others  in  Virginia, 
and  two  in  North  Carolina.  The  coarse  Potomac 
marble  is  from  the  lower  part  of  the  Trias. 

It  is  now  the  middle  part  of   the  Mesozoic  Mon.  The  hey- 
We  are  in  the  midst  of  the  reign  of  reptiles.    This  dy-  ^  of  the 
nasty  is  even  more  pronounced  than  was  the  reign  of  R^ptnes. 
fishes.    Down  by  the   sea-shore   Mesozoic   saurians 
amuse  themselves  in  the  surf.    The  Ich'-thy-o-saur,  ichthy- 
with  thick  and  fish-like  form  and  alligator  head,  osaur. 
pursues  the  fated  fish  into  the  deeper  water,  guided  by 
a  pair  of  enormous  eyes  which  gather  in  the  feeble 
light.    The  swan-like  neck  and  head  of  the  Ple'-si-  piesi/. 
o-saur  rise  above  the  surface,  while  the  short,  thick  os<™r- 
body  is  propelled  beneath  by  a  pair  of  long,  flat, 
many-fingered   and   many-jointed   paddles.      There 
too,  winds  the  progenitor  of  the  sea-serpent — a  real 
sea-serpent,  whatever  fable  may  connect  itself  with 
the  modern  one.    This  is  the  Mos'-a-saur,  attaining  Mosasaur 
sometimes  a  length  of  eighty  feet.    The  body  is  cov- 
ered with  small,  overlapping  bony  plates.    The  pad- 
dles are  five-fingered  and  resemble  those  of  whales. 

Contemporary  with  the  sea-saurians  are  those  of  che]0. 
the  estuary  and  the  river.    Turtles  and  tortoises  sun  mans, 
themselves    on    the   naked     slopes.      Real    lizards  Lizards, 
scamper  over  the  cliffs,  or  skulk  among  the  debris 
of  the  forest.    But  most  conspicuous  of  all  move  the 
gigantic  Deinosaurs.     Some  swim  in  the  sea ;  some 
crawl  on  the  land  ;  some  scud  among  the  branches 
of  the  trees,  and  other  forms  standing  erect,  walk  in 
reptilian  majesty  among  their  humble  subjects. 

Here  is  the  Had/-ro-saur,  whose  province  is  lim-  Hadro- 
ited  to  the  Atlantic  border.    His  near  relative,  the  **wr. 
Ig-uan'-o-don,    holds    some    provinces   in    the    Old 


302      Walks  and  Talks  in  the  Geological  Field. 


Lcelaps. 


Reptiles 
every- 
where. 


World.  These  are  vegetable  eaters.  But  here  is 
their  traditional  enemy  the  carnivore.  Lce'-laps  dis- 
putes supremacy  with  the  Hadrosaur,  as  in  the  Old 
World,  Megalosaur  rivals  Iguan/odon.  Strangest  of 
Pterosaur,  all,  for  a  reptilian  modification,  the  Pter'-o-saur  sails 
over  our  heads  and  shadows  us  with  his  broad 
leathery  wing.  The  Pterosaur  is  a  ground  disputed 
between  reptiles  and  birds.  In  aspect,  bird-like,  he 
is,  however,  essentially  a  saurian.  In  structure  he  is 
less  bird-like  than  the  Deinosaur. 

What  a  range  of  adaptations  is  this ;  sea,  river, 
shore,  upland,  forest,  jungle,  and  atmosphere — all 
populated  by  fit  modifications  of  a  single  type  of 
vertebrates  !  But  we  stand  still  more  amazed.  Be- 
fore we  make  our  exit  from  this  wonderful  Mesozoic 
time,  behold  a  real  bird  on  the  wing.  Clothed  with 
proper  feathers  and  constituted  a  bird,  it  is  yet  rep- 
tilian. Its  long  and  lizard-like  tail,  vertebrated  to 
the  extremity,  is  furnished  with  proper  quills,  but 
cannot  conceal  its  kinship  with  the  reptiles.  It  comes 
out  of  the  empire  of  reptiles  and  brings  reminiscen- 
ces of  the  reptiles  with  it. 

A  higher  type  is  now  standing  at  the  threshold  of 
being.  A  knell  is  sounding  the  funeral  of  the  rep- 
tilian dynasty.  The  saurian  hordes  shrink  away  be- 
fore the  approach  of  a  superior  being.  After  a  splen- 
did reign,  the  dynasty  of  reptiles  crumbles  to  the 
ground,  and  we  know  it  only  from  the  history  writ- 
ten in  its  ruins. 


Mammalian  Rule.  303 


XLIV.     MAMMALIAN  EULE. 

C^NOZOIC  TIMES. 

THE  striking  figures  which  appealed  to  our  wonder  The  first 


during  our  walk  through  the  Mesozoio  ^Eon,  diverted 
attention  from  some  very  humble  but  very  suggestive  date  from 
creatures  which  managed  to  elude  the  dangers  threat-  the  Tri- 
ening  them  under  a  rule  which  knew  only  cruelty 
and  extermination.  These  creatures  were  little 
mammals.  The  first  species  found  to  have  existed 
in  America  was  found  by  Professor  Emmons  in  the 
red  sandstone  of  North  Carolina.  The  lower  jaw  is 
armed  with  a  series  of  teeth  somewhat  like  those  of 
the  common  mole.  It  seems,  therefore,  to  have  been 
insectivorous.  Its  nearest  relative  among  living 
mammals  is  the  Banded  Anteater  of  Australia,  a 
small  animal  with  a  fox-like  appearance.  We  call  it 
Drom-a-the'^ri-um,  or  "  Running-beast."  It  is  sin-  Thelr 
gular  that  a  very  similar  mammal  lived  in  the  same  character. 
age  in  the  Old  World.  Some  of  its  remains  have 
been  found  at  Wiirtemberg,  and  others,  at  Frome, 
England.  Another  Triassic  mammal  has  recently 
been  described  by  Professor  Owen  from  South 
Africa,  as  large  as  a  gray  fox,  and  remarkably  special- 
ized. All  these  mammals  are  most  distinctly  mam- 
malian. Whatever  the  origin  of  these  little  forerun- 
Iners  of  a  noble  type,  it  can  not  be  supposed  they  had 
no  companions.  There  must  have  been  hundreds,  if 
not  thousands,  of  individuals  of  each  of  these  species, 
but  they  are  wholly  lost  to  knowledge.  Where  we 
are  sure  of  the  disappearance  of  so  many  remains, 


304      Walks  and  Talks  in  the  Geological  Field. 

how  easy  to  believe  the  remains  of  different  creatures 
— of  lower  mammals — have  also  disappeared. 
Aitho'  Mammals  once  in  existence,  we  are  compelled  to 

urea  InSe  believe  that  thev  continued  uninterruptedly  in  exis- 
Jura-Tri-    tence  until  our  own  times.    We  cannot  admit  that 
assic.they  the  t          wag  logt  to  the  world   and  then  the  game 
are  almost 
unknown  identical  conception  reintroduced.     But  where  did 

in  the  Ore-  mammais  iive  ;  where  did  they  perish ;  where  lie 
taceous. 

their  bones?    Save  one  or  two  thin  bone  beds,  we 

search  in  vain  the  depth  and  breadth  of  Jurassic  and 
Cretaceous  strata  for  evidences  of  the  existence  of 
mammals.  In  a  bone  bed  of  the  Stonesfield  Slate  of 
the  English  Jurassic,  the  teeth  and  jaws  of  several 
species  of  mammals  have  been  found.  These  are 
mostly  near  relatives  of  the  Triassic  mammals.  In 
the  Middle  Purbeck  of  the  Upper  Jurassic,  occur 
other  remains.  We  know  in  Europe,  all  together, 
not  much  over  fourteen  species,  and  they  are 
probably  all  marsupial ;  and  a  majority  are  insecti- 
vores.  In  the  Jurassic  of  America,  Professor  Marsh 
has  brought  to  light  at  least  17  species  ;  and  these  all 
closely  resemble  the  Old  World  remains.  In  all  the 
vast  thickness  of  the  Cretaceous  strata,  but  a  single 
species  is  known,  and  of  this  so  far  as  I  am  informed, 
but  a  single  individual,  and  this  very  imperfectly 
preserved.  It  comes  from  Dakota,  and  was  described 
in  1884  by  Professor  Cope,  who  bestowed  on  it  the 
name  Men-is-co-es'-sus.  This  also,  is  similar  to  the 
Old  World  forms. 

Thus  all  the  intimations  show  that  while  the 
mammalian  type  had  already  made  great  advance  in 
the  Mesozoic  ^Eon — almost  equally  advanced  at  the 
beginning  and  end — it  was  still  but  meagerly  de- 


Mammalian  Rule.  305 

veloped.  Its  affinities,  even  to  the  end  of  the  Meso- 
zoic,  were  with  the  lower  division  of  mammals,  the 
Marsupials.  With  so  little  progress  between  the 
Triassic  and  the  end  of  the  Cretaceous,  we  are  re- 
minded again,  that  a  long  interval  of  mammalian 
existence  must  have  passed,  before  the  Triassic  Drom- 
atherium  took  its  place  in  the  world. 

With  the  opening  of  Csenozoic  time  all  is  changed.  But  ^^ 
The  transition  reminds  us  of  that  from  the  Eozoic  to  in  Cseno- 
the  Palaeozoic.  The  world  is  now  astir  with  mam- 


malian  life  of  considerable  development  in  rank  and  life  is 
diversification    of  type.      When    was   this  advance      ,  ,. 
effected?     Probably  during  the  Cretaceous.     Then  verse. 
we  must  admit  that  the  sole  Cretaceous  mammal 
known    fails    to  represent  the  average  of  the  Cre- 
taceous.   But  a  glance  over  the  assemblage  of  early 
Tertiary  mammals  at  once  shows  them  stamped  with 
inferior  characteristics.    They  are  all  greatly  general-  General. 
teed  —  that  is,  some  characters  of  two,  three,  or  more  ized  types. 
of  our  modern  orders  are  blended  in  one  individual. 
This  principle  is  exemplified  in  the  early  representa- 
tives of  every  group  of  animals.     In  the  next  place, 
they  possessed  small  brains.     If  we  compare  one  of 
them  with  its  nearest  relative  in  any  later  age,  and 
especially  with  a  modern  mammal,  the  disparity  in 
brain  is  striking.    Enlargement  of  brain  is  a  strong 
mark  of  advancement.    Another  circumstance  is  the 
generally  pentadactyl  character  of  these  mammals. 
To  have  five  toes  on  each  foot  may  be  thought  a 
mark  of  superiority,  since  man  has  five.     But  five  is 
the  typical  or  fundamental  number.     This  is  pos- 
sessed by  many  reptiles  and  by  most  of  the  lowest 
mammals.    Advance  has  been  marked  by  modifica- 


306     Walks  and  Talks  in  the  Geological  Field. 


tions,  and  these,  as  a  fact,  have  involved,  in  most 
cases,  a  reduction  in  the  number  of  digits.  The  ex- 
tremities of  man  may,  therefore,  be  regarded  as  more 
primitive  than  those  of  the  dog  with  four  digits,  the 
ox,  with  two  digits,  and  the  horse  with  one.  This  at 
least  is  the  prevailing  scientific  opinion  ;  but  I  ven- 
ture to  contest  it.  Finally,  most  of  the  early  Ter- 
tiary mammals  were  plantigrade  ;  that  is,  they 
walked  on  the  whole  length  of  the  foot,  with  the 
heel  on  the  ground  ;  while  most  mammals  walk  on 
the  toes  with  the  heel  elevated—  the  ''hock"  being 
the  heel.  This  also  may  be  thought  a  mark  of  supe- 
riority, since  man  is  a  plantigrade;  but  digitigrade 
walking  sustains  the  same  relation  as  pentadactyl- 
ism,  to  progressive  advance. 

One  of  the  first  figures  to  greet  us  on  our  entering 
Cfenozoic  times  is  Co*ryph'-o-don,  one  of  the  best  ex- 
amples  °f  a  generalized  type.  As  large  as  a  Malayan 
tapir,  with  similar  short  legs,  it  had  no  other  charac- 
ters of  the  tapir,  or  of  other  hoofed  quadrupeds 
(Ungulates).  It  had  the  full  number  of  the  different 
sorts  of  teeth  ;  five  toes  on  each  foot  ;  nose  not 
adapted  for  work  as  in  the  tapir,  hog,  and  elephant  ; 
canine  teeth  prominent  as  in  hogs  and  Carnivores. 
The  feet  were  somewhat  elephant-like,  and  the  head, 
anterior  to  the  eyes,  was  long,  as  in  the  horse,  and 
the  whole  range  of  incisors  was  horse-like.  Here, 
also  was  Hy-rach'-y^us,  more  tapir-like,  with  four 
toes  in  front  and  three  behind.  Here  further,  were 
two  forms  more  related  to  the  horse,  but  only  as  large 
EoMppus  as  a  f°x  —  Eo-hip'-pus  (Dawn-horse)  and  O-ro-hip'^pus 
(Mountain'norse)-  They  had  four  perfect  toes  in 


Eocene 
types. 


H  rach_ 

yus. 


Orohi    us 


front  and  three  behind  ;  but  in  spite  of  the  number 


Mammalian  Rule,  307 

of  toes,  they  showed  their  affinities  with  the  horse  in 
several  particulars  of  structure  of  the  leg  and  foot- 
bones  and  in  the  teeth. 

A  little  later,  the  forms  of  huge  and  curious  mam- 
mals  crowd  on  our  view.  Til-lo-the'-ri-um  (Biting-  rium- 
beast)  had  enormous,  long  incisors,  two  in  number, 
much  like  the  beaver  ;  but  it  was  not  a  real  Rodent, 
or  gnawer.  Dirnoc'-e-ras  (Fearful-horn)  was  like  an  Dinoceras 
elephant  in  size.  It  had  short  legs  and  perhaps  three 
pairs  of  horns— one  on  the  snout,  one  on  the  cheeks, 
and  one  on  the  forehead.  These  must  have  given  the 
creature  a  grotesque  and  fierce  aspect.  Its  habits  ap- 
pear to  have  been  like  those  of  the  rhinoceros.  It 
was  five  toed,  like  Coryph'odon,  and  in  other  respects 
was  related— widely  different  as  it  was  nevertheless. 
The  Dinoc'eras  had  for  relatives  U-4n-ta-the/rium  „. 

uintathe- 

(Beast  of  the  Uintas)  and   Ti-noc'e-ras  (Avenging-  num. 
horn).    This  must  ha/ve  been  the  ruling  family  of  Tinoceras. 
beasts  during  the  Eocene,  or  earlier  Tertiary.     Only 
a  few  mammals  related  to  the  /ox,  wolf,  cat,  bat,  and 
squirrel  had  yet  appeared  on  the  scene.     There  was  a 
marked   tendency   toward   the  tapir  type,  the  rhi- 
noceros type,  and  the  horse  type.    Some  even-toed 
Ungulates  came  at  last — Par-a-me'-ryx  (Ruminant-  Parame- 
like)  which  had  relations  to  camels  and  stags — and  rvx- 
were  really  the  precursors  of  the  true  Ruminants 
(Cud-chewers). 

In    the    Miocene    or  Middle  Tertiary,   the    tapir,  Miocene 
rhinoceros,  and  horse  tendencies    continued.      The  types. 
Ruminant   tendency    also   continued.      But     there 
was    developed,  also,  a    tendency  to  the  hog   and 
the  sheep.     In  fact,  the  hog  and  sheep  were  some- 
what united  in  O-re'-o-don  (Mixed-tooth),  for  which  oreodon. 


308      Walks  and  Talks  in  the  Geological  Meld. 


Menodus.    reason  Leidy  styles  it  "  a  ruminating  hog.  •*'     Menf-o- 
dus  (strong-tooth)  was  intermediate  between  Dino</- 
Sronto-      eras  an<l  Tapir.    It  was  large  as  an  elephant.    JBron- 
therium.     to-the'-ri-um  (Thunder-beast)  was   of  similar    bulk, 
and  had  a  pair  of  horns.    Now  came,  also,  the  in- 
crease of  Carnivores.      Ma-chcer-o-dus   (Saber-tooth) 
was  as  large  as  a  lion,  with  fearful,  tearing  canines. 
Hy-cenf-o-don  (Hyaena-tooth)  was  as  big  as  a  black 
bear.     Insectivores  existed,  and  now  appeared  the 
earliest  of  the  beavers. 

In  the  Pliocene  or  late  Tertiary,  we  witness  a 
marked  approximation  to  modern  genera.  Now  the 
equine  type  had  become  almost  a  horse.  Here  were 
camels,  rhinoceroses,  tapirs.  Here  the  first  elephants 
came  upon  the  scene,  though  elephantine  characters 
had  been  in  the  world  through  the  whole  Tertiary. 
Mastodons  were  perhaps  earlier.  The  lowest  mon- 
keys (Lemurs)  had  existed  from  the  Eocene  ;  and 
proper  tailed  monkeys  from  the  Miocene.  But  in  all 
this  teeming  procession  of  mammals  we  notice  no 
sign  of  man— save  only  the  prophecy  of  man. 


Machcer- 
odus. 


Hycen- 
odon. 


Pliocene 
types. 


XLY.      ANTICIPATION    AND    BETROSPECT    IN 
LIFE  PLANS. 


COMPREHENSIVE  TYPES. 

Definition      WHAT  I  wish  now  to  set  forth  is  a  principle  of 

of  com-       very  profound  significance.      It  is  a  general  truth  in 

types.         the  nature  of  the  succession  of  organic  types  ;  and  I 

will  endeavor  to  make  it  plain  by  citing  some  of  the 

striking  illustrations  of  it.      From  the  working  of 

this  principle,  it  results  that  the  creatures  of  any 


Anticipation  and  Retrospect  in  Life  Plans.    309 

age  often  unite  in  themselves  some  characters  of  a 
group  actually  existing,  with  characters  of  a  group 
not  yet  in  existence.  This  is  anticipation.  Such  a 
union  forms  a  "prophetic  type,"  as  Agassiz  used 
to  express  it.  It  is  also  a  comprehensive  type.  Also, 
from  the  working  of  this  principle,  it  results  that  the 
creatures  of  any  age  often  unite  in  themselves  some 
characters  of  a  group  actually  existing,  with  charac- 
ters of  a  group  which  was  dominant  in  a  former  age 
— whether  still  existing  or  not.  Such  a  union  forms 
a  retrospective  type.  This  is  also  comprehensive. 
But  in  some  comprehensive  types  we  find  a  union  of 
characters  none  of  which  belong  to  any  fairly  cir- 
cumscribed existing  group.  They  are  all  prophetic 
or  anticipatory  of  groups  which  are  destined  to  be  de- 
fined in  the  future. 

Take  first  the  early  Ganoids  for  a  good  example.  Exam. 
Their  vertebrae  were  generally  concavo-convex.  This  Ples. 
is  a  reptilian  character.  Nearly  all  reptiles,  living  Ganoids> 
and  extinct,  possess  such  vertebrae,  while  all  typical 
proper  fishes  possess  biconcave  vertebrae.  Now 
the  early  Ganoids  were  not  reptiles,  and  had  no 
claim  to  concavo-convex  vertebrae.  There  had  never 
been  a  reptile  in  existence  when  these  Ganoids  first 
lived — when  O-nych'-o-dus  of  Ohio,  for  instance, 
flourished.  If  we  may  attribute  to  the  ancient 
Ganoids  certain  other  characters  which  belong  to 
modern  Ganoids,  like  the  gar-pike,  we  should  say 
they  possessed  an  opening  or  glottis  in  the  back  part 
of  the  mouth,  and  that  a  passage  existed  from  this  to 
the  air  bladder ;  and  that  the  latter  organ  was 
coarsely  vesicular,  giving  a  rough  imitation  of  a  lung. 
The  gar-pike  too,  is  capable  of  a  vertical  motion  of 


310      Walks  and  Talks  in  the  Geological  Meld. 

the  head ;  that  is,  unlike  all  other  modern  fishes,  it 
has  a  neck,  and  can  raise  the  head,  like  a  reptile. 
The  ancient  Ganoids  were  certainly  not  less  reptilian 
than  the  modern  ones.  The  possession  of  bony 
armor  is  also  a  reptilian  prerogative  ;  and  it  may  be 
added,  that  the  teeth  of  the  ancient  Ganoids  were 
truly  reptilian.  Those  of  Onychodus  were  strikingly 
so.  As  in  reptiles,  too,  the  vertebral  column  con- 
tinued to  the  end  of  the  tail.  Thus  the  ancient 
Ganoids  possessed  several  reptilian  characters  ;  while 
in  general  form,  they  were  fish-like ;  in  aquatic 
respiration,  in  many  rayed  fins,  in  cranial  and  general 
skeletal  structure  they  were  fishes.  Thus  the  ancient 
Ganoids,  and  to  a  similar  extent,  the  modern  ones, 
were  a  comprehensive  type.  They  anticipated  rep- 
tiles; they  were  prophetic  of  reptiles.  Later  the 
ganoid  type  was  resolved.  The  ichthyic  characters 
were  retained  in  one  organism,  and  the  reptilian  were 
gathered  together  in  a  different  organism.  How  did 
it  occur  that  an  animal  on  the  whole  a  fish,  should 
incorporate  in  its  structure  features  of  a  class  which 
was  yet  far  in  the  future  ? 

Amphib-  The  Amphibians  are  a  comprehensive  type.  Struc- 
ians.  turally  they  partake  of  the  natures  of  fishes  and  of 
reptiles.  They  are  fish-like  in  branchial  respiration 
during  early  life.  They  are  fish-like  in  the  posses- 
sion of  biconcave  vertebrae  ;  in  having  two  occipital 
condyls,  and  in  other  less  conspicuous  characters  of 
the  skull ;  in  the  organs  which  serve  as  kidneys  ;  and 
among  Batrachians  (frog-like)  in  the  double  septum 
which  divides  the  orbits — which  is  a  ganoid  charac- 
ter. They  are  reptilian  in  breathing  air  in  adult  life  ; 
in  the  possession  of  appendages  for  locomotion  on 


Anticipation  and  Retrospect  in  Life  Plans.    311 

land,  and  in  the  undivided  ventricle  of  the  heart. 
The  nervous  system  is  intermediate  between  fishes 
and  reptiles.  The  extinct  Labyrinthodont,  while 
possessing  many  distinct  batrachian  affinities,  was 
reptilian  in  its  crocodile-like  skull,  and  the  protective 
bony  plates  upon  the  thorax  and  flanks.  In  the 
teeth  is  found,  however,  the  peculiar  labyrinthine 
structure  seen  in  some  Placoderm  fishes  ;  and  the 
sculptured  plates  of  the  Ganocephala  furnish  a  re- 
semblance to  bony  scaled  Ganoids.  The  structure  of 
Amphibians  is  on  the  whole,  so  reptilian  that  they 
were,  for  many  years,  merged  in  the  reptile-class. 
Now  Amphibians  existed,  as  far  as  we  know,  before 
the  reptile-type  had  been  introduced.  All  their  rep- 
tilian characters,  therefore,  were  prophetic  of  a  class 
which  was  yet  non-existent.  On  the  contrary,  they 
appeared  when  the  reign  of  fishes  was  passing  away. 
All  their  ichthyic  characters,  therefore,  were  retro- 
spective. 

Take  next,  the  wide-ranging  class  of  Reptiles.  The 
During  the  age  of  its  dominance,  various  ordinal  di-  ancient 
visions  exemplified  various  relations  to  the  future 
and  the  past.  While  the  concavo-convex  vertebra 
was  proper  to  reptiles,  the  sea-saurians  had  bicon- 
cave vertebrae — a  reminiscence  of  fishes.  Other  rep- 
tiles had  the  teeth  soldered  to  the  jaws  as  in  fishes. 
Some  reptiles  with  socketed  teeth,  however,  had  bi- 
concave vertebrae.  The  Ichthyosaur  with  fish-like 
vertebrae  and  jaws,  had  crocodilian  teeth  and  whale- 
like  paddles.  It  looked  forward  toward  the  mam- 
malian type.  Some  of  the  Deinosaurs,  also,  were 
prophetic  of  land-mammals  in  their  short,  compact 
bodies,  while  their  bipedal  attitude  anticipated  both 


312     Walks  and  Talks  in  the  Geological  Field. 

mammals  and  birds.  A  more  explicit  anticipation 
of  birds  was  revealed  in  the  composition  of  the  dig- 
its and  the  structures  of  the  tarsus  and  pelvis.  The 
Pterosaurs  were  prophetic  of  bats  in  their  leathery 
wings  supported  by  elongated  digits.  They  fore- 
shadowed birds,  not  alone  in  the  flying  function, 
but  in  their  bird-like  scapula,  coracoid,  and  other 
structures.  In  one  genus  the  tips  of  the  mandibles 
were  without  teeth  ;  and  in  the  American  Ptero- 
saurs, the  mandibles  were  completely  destitute  of 
teeth,  while  the  tail,  also,  is  reduced  to  a  few  verte- 
brae, and  the  head  is  distinctly  bird-like. 

The  gradation  of  reptiles  towards  birds  brings  us  to 
facts  still  more  remarkable.  In  the  Jurassic  slates  of 
Solenhofen  in  Bavaria,  which  have  yielded  speci- 
mens of  Pterodactyls  retaining  the  impression  of 
•  the  leathery  wing,  have  been  found,  also,  remains  of 
a  bird  which  had  a  long  vertebrated  tail,  like  a  lizard, 
with  a  pair  of  quills  standing  out  from  each  verte- 
bra. It  had  also,  saurian  teeth  inserted  in  sockets. 
It  had  a  true  bird-foot,  except  that  the  metacarpals 
were  separate.  This  wonderful  compound  of  bird 
and  reptile,  after  causing  much  discussion,  was 
finally  assigned  a  place  among  birds  and  named 
The  first  Ar-chce-op' '-ter-yx  or  "old-flyer."  Very  recently,  how- 
Birds,  ever,  other  specimens  have  been  found,  and  Carl 
Vogt  of  Geneva,  after  careful  examination,  declares 
that  the  creature  was  a  feathered  lizard,  and  not  a 
bird.  There  are  two  conical  teeth  in  the  upper  jaw  ; 
eight  neck-vertebrae,  with  five  pairs  of  ribs  directed 
backwards ;  ten  dorsal  vertebrae  without  spinous  pro- 
cesses, and  supporting  ribs  without  uncinate  pro- 
cesses ;  five  sternal  ribs  and  very  minute  sternum. 


Anticipation  and  Retrospect  in  Life  Plans.    313 

The  fore-limb,  he  maintains,  is  not  a  proper  wing, 
and  there  are  three  digits  resembling  those  of  a 
clawed  lizard  ;  the  feathers  are  attached  to  the  side 
of  the  arm,  hand,  body,  legs,  and  tail.  If  the  feathers 
had  not  been  preserved,  no  one  would  have  thought 
this  Old-flyer  a  bird,  or  capable  of  flight.  Now 
what  can  we  say  of  a  creature  having  the  bird  and 
reptile  so  mixed  that  the  best  judges  are  unable  to 
decide  whether  it  is  one  or  the  other  ? 

The  Cretaceous  Age  in  America  produced  still  other 
mongrel  forms,  which  have  been  published  to  the 
world  by  Professor  Marsh.  These  seem  to  lean  un- 
mistakably toward  the  side  of  birds ;  but  they  pos- 
sessed saurian  teeth,  and  are  known  as  O-dont-or'- 
ni-thes  or  "Toothed-birds."  There  are  two  genera. 
Ich-ihy-or'-nis  or  "  Fish-bird,"  had  strong  wings,  bi- 
concave (fish-like)  vertebrae,  and  teeth  inserted  in 
sockets.  Hes-per-or'-nis  or  "  Western-bird "  had 
feeble  wings,  and  teeth  inserted  in  grooves  along  the 
crests  of  the  jaws. 

From  such  examples  as  have  been  cited,  it  will  be  Compre- 

understood  that  the  principle  of  comprehensive  types  hensive 

types 

results  in  gradational  relations.      That  is,  organic  become 
forms,  recent  or  fossil,  may  be  arranged  in  series  ac-  sPeciaI- 
cording  to  structural  relationships.    The  forms  more 
or  less  bird-like,  for  instance,  may  be  ranged  in  a 
column  beginning  with  most  highly  developed  birds, 
and  ending  with  characteristic  saurians.    We  find, 
indeed,  two  series,  and  may  arrange  them  as  follows  : 
I.    FROM  RUNNING-BIRDS  BACK  TO  REPTILES. 

1.  Struthious  Birds,  ostrich-like,  feeble  wings,  runners. 

2.  Brontozo'ilm,  bipedal,  three-toed,  with  phalanges 

bird-like. 


314     Walks  and  Talks  in  the  Geological  field. 

From  rep-  3.  Laosau'rus,  bird-like  in  head,  ischiac  and  post- 
tiles  to  pubic  bones  and  toes. 

Wrd"inS     4'  Compsog'nathus,  bird-like    in  head,  consolidated 
astragalus  and  tibia. 

5.  Anomce'pus,  four  toes  before,  three  bird-like  toes 

behind. 

6.  Hadrosau'rus,  weak  fore-legs,  attitude  bipedal. 

7.  Bhynchosau' VMS,  saurian,  with  toothless  mandibles, 

bipedal. 

8.  Iguan'odon,   tips  of  premaxillaries  toothless,   ob- 

liquely bipedal. 

II.    FROM  CABIN  ATE  BIRDS  BACK  TO  REPTILES. 

From  rep-  1.  Carinate  JBirds,  sternum  keeled,  flying  birds, 
tiles  to  fly-  2.  Hesperor'nis,  with  poor  wings,  teeth  in  grooves, 
ing  birds.  3   ichthyor'nis,  with  good  wings,  socketed  teeth,  bi- 
concave vertebrae. 

4.  Archceop'teryx,    bird    or    lizard,  tail   long,    teeth 

socketed,  metacarpals  separate. 

5.  Pteran'odon,  winged  reptile,  short  tail,  no  teeth, 

bird-like  head. 

6.  RamphorJiyn'chuSi  winged  reptile,  distant,  sharp 

and  curved  teeth,  horny  tips  of  mandibles,  long 
tail. 

7.  Pterodac'tylus,  winged   reptile,  bird-like  scapula 

and  coracoid. 

8.  Thec'odont  Saurians,  typical  saurians  with  sock- 

eted teeth. 

Here  are  two  lines  of  gradation  from  reptiles  to 
birds,  arranged  out  of  extinct  forms.  It  must  be 
stated,  however,  that  their  order  of  succession  in 
time  does  not  correspond  with  their  relative  position 
in  the  gradation.  But  we  know,  as  yet,  so  little 
about  the  complete  fauna  of  different  ages,  that  it 
would  be  rash  to  conclude  that  the  actual  order  of 
appearance  was  not  accordant  with  their  order  in 
rank. 


Anticipation  and  Retrospect  in  Life  Plans.    315 

Let  me  now  present  a  gradation  of  forms  which 
corresponds  strictly  with  their  order  of  appearance. 

1.  Equus,  late  Pliocene.    Common  horse,  feet  reduced  From 

to  central  series  of  bones  (middle  finger  and  toe),  Eohlppus 
a  pair   of   "splints"    to  represent   second   and  to  the 
fourth  digits.  horse- 

2.  Pliohip'pm,   middle   Pliocene.     Smaller,    central 

digital  series  more  slender ;  splints  more  elon- 
gated ;  crown  of  upper  molars  shorter,  and  cres- 
centic  areas  simpler. 

3.  Protohip'pus,  early  Pliocene.    Size  of  ass  ;  central 

digital  series  still  more  slender  ;  splints  termi- 
nated by  dangling  hooflets ;  ulna  long  as  arm, 
but  slender ;  fibula  rudimentary  ;  crowns  of  mo- 
lars much  shorter. 

4.  Miohip'pus,  of  late  Miocene.     Size  of  sheep  ;  three 

functional  toes  before  and  three  behind ;  small 
splint  of  fifth  digit,  before  ;  ulna  distinct,  long  as 
radius,  but  very  slender  at  lower  end  ;  fibula  co- 
ossified  with  tibia  at  lower  end  ;  molar  crowns 
decidedly  short ;  enamel  folds  much  simpler  than 
in  horse. 

5.  Mesohip'pus,  of  oldest  Miocene.    Size  of  sheep  ; 

three  functional  toes  before  and  three  behind,  but 
more  nearly  equal  than  in  Miohippus ;  large 
splint  of  fifth  digit,  before  ;  radius  and  ulna  dis- 
tinct, and  also  tibia  and  fibula. 

6.  Orohip'pus,  of  middle  Eocene,  of  Wyoming  and 

Utah.  Size  of  fox  ;  four  functional  toes  before 
and  three  behind ;  ulna  complete  and  distinct 
from  radius  ;  tibia  and  fi  b  u  1  a  also  distinct ; 
molar  crowns  exceedingly  short ;  enamel  pattern 
simple. 

7.  Eohip'pus,  of  oldest  Eocene,  of  New  Mexico.     Size 

of  fox  ;  four  functional  toes  before  and  three  be- 
hind ;  rudiments  of  outer  or  fifth  toe  behind,  and 
hence,  probably,  of  first  digit  before  ;  hoofs  mere 
thick,  broad  and  blunt  claws  ;  molars  less  special- 
ized than  in  Orohippus,  without  cement. 


316      Walks  and  Talks  in  the  Geological  Field. 

The  affinities,  gradations,  and  successions  thus  in- 
dicated are  facts  of  observation  ;  they  depend  on  no 
theory  of  organic  history.  They  simply  show  that 
each  type  of  the  past  possessed  characters  which 
related  it  to  organisms  yet  future.  There  was  retro- 
spect ;  there  was  anticipation.  The  past  was  bound 
to  the  present;  the  present,  to  the  future.  History 
was  a  constant  unfolding  of  that  which  was  con- 
tained in  the  past.  Progress  was  a  perpetual  fulfill- 
ment of  prophecy. 


XLYI.     THE  THROES  OF  THE  CONTINENT. 

HOW  THE  LAND   GREW. 

The  con-         WHILE  the  great  plan  of  organic  life  was  unfold- 
tinent  a     ing  itself   the  continental  theater  of  its  exhibition 

growth. 

underwent  a  process  of  expansion  which  no  less 
reveals  a  plan,  and  no  less  awakens  our  interest  and 
admiration.  By  what  stages  the  region  east  of  the 
Great  Plains  acquired  its  form  and  dimensions,  has 
long  been  understood ;  but  the  method  of  the  build- 
ing of  the  western  half  has  only  been  brought  to 
light  through  the  recent  researches  of  Hayden  and 
Meek,  King  and  Wheeler,  Powell  and  Button,  Gil- 
bert and  Hague,  Whitney  and  Gabb,  and  their  com- 
peers and  collaborators. 

Theconti-      ^as^  °^  *he  Great  Plains,  rose  first  a  long,  hook- 
nent  at  the  shaped  ridge,  with  its  longer  branch  stretching  from 
Eozoic.      the  north  shores  of  the  Upper  Lakes  to  the  Arctic 
Ocean,   in  the  region    between  Hudson's  Bay  and 
McKenzie's    River ;  while  the    shorter    branch    ex- 
tended northeastward  as  far  as  the  coast  of  Labrador. 


The  Throes  of  the  Continent.  317 

Not  improbably  this  branch  stretched  across  the 
North  Atlantic  to  the  British  Islands  and  Scandi- 
navia. This  primitive  area  I  have  styled  the  Great 
Northern  Land.  It  is  also  known  as  the  Laurentian 
area— a  name  which  applies  properly  only  to  the  por- 
tion sustaining  some  contiguity  to  the  St.  Lawrence. 

Along  the  low  seaboard  region  east  of  the  Appa- 
lachians, stretches,  from  Maine  to  Alabama,  the 
stump  of  an  ancient  mountain  range  which  appears 
to  have  been  of  the  same  age.  The  stump  only,  I 
say,  for  the  tooth  of  time  has  gnawed  it  nearly  level 
with  the  sea,  and  the  old  material  has  been  rebuilt  in 
the  foundations  of  later  lands.  This  was  the  great 
Seaboard  Land. 

West  of  the  Great  Plains,  as  we  now  understand, 
stretched  another  long  belt  of  land,  which  was  des- 
tined eventually  to  be  consolidated  with  the  eastern 
lands,  to  form  the  continent.  In  width,  it  extended 
originally — that  is,  at  the  beginning  of  the  Palaeozoic 
2Eon,  from  the  eastern  bases  of  the  Rocky  Mountains 
to  western  Nevada— probably  seven  hundred  and 
fifty  miles  ;  in  length,  it  stretched  far  northward  and 
southward,  to  distances  not  yet  ascertained.  This 
was  the  Great  Cordilleran  Land.  There  were  prob- 
ably other  small  land  areas,  rising  like  islands  from 
the  universal  ocean  ;  and  there  may  have  been  other 
areas  of  moderate  continental  extent ;  but  so  far  as 
our  probable  knowledge  goes,  the  three  continental 
expanses  mentioned  were  the  chief  beginnings  of 
North  America. 

The  Cordilleran  Land  was  a  great  mountain  sys- 
tem, displaying  lofty  ranges  made  of  crumpled 
strata  ;  enormous  precipices,  the  result  of  mechan- 


318     Walks  and  Talks  in  the  Geological  Meld. 

ical  dislocation ;  and  finally,  a  type  of  mountain 
sculpture,  of  such  broad,  smooth  forms  as  to  warrant 
the  belief  that  subaerial  erosion  had  never  carved 
and  furrowed  the  mountain  flanks  with  the  sharp 
ravines  characteristic  of  modern  mountain  topog- 
raphy. This  massive  belt  of  Eozoic  Cordilleras  de- 
termined the  limits  of  the  modern  Cordilleras,  and 
very  much  of  the  details  of  their  fundamental  struc- 
ture. 

Such  was  America  in  the  twilight  of  its  history. 
There  must  have  been,  however,  as  I  have  argued  in 
Talk  XXXIX.,  some  lands  which  had  now  dis- 
appeared. These  surviving  germinal  nuclei  are  com- 
posed of  stratified  rocks.  Older  rocks  had  been  re- 
duced to  sediment  in  supplying  material  for  the 
building  of  the  lands  which  are  the  oldest  now  re- 
maining. Let  us  see  what  vicissitudes  these  lands 
were  destined  to  undergo. 

Geography     The    first  seon  of  the  ocean's  history    was    past. 

Cumbrian  Witn  the  °PeninS  of  *ne  second,  nearly  the  whole  of 
the  Cordilleran  Land  began  to  subside.  It  sank  until 
only  the  mountain  masses  rose  as  rugged  islands 
above  the  sea-level.  Only  the  western  border  held 
its  position.  This  remnant  of  the  Cordilleran  Land 
stretched  along  western  Nevada  and  eastern  Califor- 
nia. The  continent  eastward  became  an  archipelago. 
Cambrian  sediments  were  deposited  over  all  its 
scarred  and  broken  surface.  One  ocean  stretched 
from  western  Nevada  to  New  England.  Whether 
the  Atlantic  Seaboard  Land  rose  or  subsided,  we  are 
unable  to  say.  Probably  it  sank,  and  its  original  ex- 
tent became  concealed  by  overlapping  Cambrian 
sediments.  The  Great  Northern  Land,  however,  be- 


The  Throes  of  the  Continent.  319 

gan  a  slow  upward  movement,  which  was  destined  to 
continue  through  all  Palaeozoic  time. 

In  the  progress  of  the  Palaeozoic  ages,  the  tenor  of  Of  the  re. 
continental  history  was  an  almost  continuous  emer-  mainder 
gence  of  the  Laurentian  portion  of  the  Northern 
Land,  and  a  continuous  sinking  of  the  Cordilleran 
Land.  The  Laurentian,  accordingly,  continued  to 
broaden  its  base  as  the  remnants  of  the  Cordilleran 
continued  to  grow  less.  The  Cordilleran  subsidence 
was  greatest  toward  the  shore  of  the  Nevada  conti- 
nent, which  was  undergoing  vast  wastage  in  supply- 
ing the  sediments  which  overspread  the  surface  of  the 
sunken  Cordilleran  region.  Coarse  and  thick  toward 
the  west,  they  became  finer  and  thiner  eastward.  By 
the  close  of  Palaeozoic  time,  the  sediments  accumula- 
ted over  the  Cordilleran  Land  were  one  thousand  feet 
thick  in  the  Rocky  Mountains,  thirty-two  thousand 
feet  in  the  Wahsatch  region,  and  forty  thousand  feet 
at  the  extreme  western  Palaeozoic  limit,  longitude 
117°  3CK  west.  Only  a  few  granitic  islands  interrupted 
the  continuity  of  the  uppermost  Carboniferous 
sheets,  from  Nevada  to  the  Great  Plains.  The  an- 
cient Eozoic  topography  was  buried  irretrievably  out 
of  sight — save  where,  in  later  times,  local  uplifts 
brought  it  again  up  to  observation.  The  Appalachian 
region,  meanwhile,  underwent  a  similar  subsidence. 
There  are  some  reasons  for  supposing  this  region  was, 
at  the  beginning  of  Palaeozoic  time,  annexed  to  the 
western  border  of  the  Seaboard  land.  If  so,  the  con- 
ditions here  were  a  sinking  land  loaded  with  sedi- 
ments derived  from  a  wasting  stationary  land  on  the 
east ;  as  in  the  west,  the  situation  was  the  same,  but 
with  the  wasting  land  on  the  west.  West  and  east 


320     Walks  and  Talks  in  the  Geological  Field. 

the  fixed  and  wasting  land  was  oceanward  from  the 
sinking  area. 

Great  changes  now  took  place.  The  Nevada  con- 
tinent, which  had  yielded  thousands  of  cubic  miles 
of  Palaeozoic  sediments,  now,  in  its  turn,  went  down, 
and  a  broad  region  eastward,  as  far  as  the  Wahsatch 
Mountains,  came  up.  The  Cordilleran  continent  was 
now  located  in  the  region  at  present  known  as  the 
"  Basin  Province,"  embracing  Great  Salt  Lake,  Pyr- 
amid Lake,  and  others.  Only  the  foundations  of  the 
Sierra  Nevada  had  been  laid.  The  Basin  continent 
on  the  east  was  to  be  ground  up  to  supply  the  ma- 
sonry for  a  new  structure  ;  just  as  the  Nevadan  foun- 
dation itself  was  the  mere  stump  of  a  land  pulver- 
ized to  supply  materials  for  the  Basin  Land.  So 
nature's  method  is  to  build,  demolish,  and  rebuild. 
As  in  the  successions  of  life,  so  in  the  successions  of 
continents. 

But  while  this  continental  see-saw  was  in  progress 
west  of  the  Wahsatch,  all  remained  quiet  to  the  east, 
as  far  as  the  Great  Plains.  In  the  Appalachian  re- 
gion, however,  a  similar  see-saw  occurred.  The 
loaded  Appalachian  belt  came  up  in  a  series  of  moun- 
tain folds  fifteen  thousand  feet  high,  while  the  Sea- 
board Land,  that  had  been  wasted  in  supplying  the 
load,  went  down — most  of  it,  like  the  old  Nevadan 
continent,  below  sea-level.  Simultaneously,  the 
whole  breadth  of  the  country  westward  to  the  Great 
Plains,  was  finally  annexed  to  the  eastern  limb  of 
North  America. 

North  it  was  now  the  beginning  of  the  geologic  Middle 

during  the  Ages-     East  of  western  Kansas,  the  land  was  com- 
Mesozoic.   pleted,  save  the  Atlantic  and  Gulf  border.    West  of 


The  Throes  of  the  Continent.  321 

the  same  meridian  stretched  a  broad  ocean — over  the 
region  of  the  Great  Plains ;  across  the  belt  of  the 
Rocky  Mountains,  where  it  was  interrupted  by  the 
meridionally  disposed  Colorado,  Medicine  Bow,  and 
Park  Ranges  ;  across  the  broad  Plateau  region  of  the 
present,  to  the  base  of  the  newly  uplifted  Basin  Land 
— which  was  now  melting  away  under  the  sedimen- 
tary demands  for  Mesozoic  materials  on  the  east  and 
the  west.  To  the  south,  this  ocean  extended  to  the 
Gulf  of  Mexico.  Northward,  it  joined  the  Arctic 
Ocean.  West  of  the  Basin  continent,  the  sediments 
of  the  Triassic  and  Jurassic  formations  were  laid 
down  unconformably  on  the  eroded  Eozoic  surface 
which  had  sunken.  East  of  the  Basin  continent,  the 
new  sediments  were  spread  conformably  on  the  last 
Carboniferous  sheets.  At  the  close  of  the  Jurassic 
Age,  these  sediments  had  attained  on  the  west,  a 
thickness  of  twenty  thousand  feet.  On  the  east,  they 
were  less  than  four  thousand  feet. 

Now  rose  the  vast  crumpled  folds  of  the  Sierra  Ne- 
vada,1 adding  two  hundred  miles  to  the  Basin  conti- 
nent on  the  west,  and  stretching  southward  at  least 
to  the  thirty-sixth  parallel,  and  northward  to  Alaska. 
East  of  the  Wahsatch,  however,  everything  still  re- 
mained quiet — save  that  the  great  orographic  event 
of  the  west  sent  its  rock-fragments,  pebbles,  and 
sands  eastward  over  the  ocean's  floor  as  far  as  Kan- 
sas, forming  the  conglomeritic  Dakota  Group  at  the 
base  of  the  Cretaceous. 

No  further  orographic  disturbances  took  place  until 
the  close  of  the  Cretaceous.  To  this  epoch,  the  sedi- 

i  The  reader  is  recommended  to  make  a  table  of  North  Ameri- 
can mountain  ranges  in  the  order  of  their  formation.  F.  S. 


322     Walks  and  Talks  in  the  Geological  Field. 

mentary  sheets  had  been  laid  down  in  conformable 
positions  continuously  from  the  Cambrian  upward. 
Now,  however,  came  the  turn  of  the  region  at  "pres- 
ent known  as  the  "  Plateau  Province."  Upward  and 
undulatory  movements  were  experienced  from  the 
region  of  the  Great  Plains  to  the  base  of  the  Wah- 
satch.  Now  rose  the  broad,  flat,  east-and-west  anti- 
clinal known  as  the  Uinta  Mountains  ;  and  the  whole 
mass  on  the  east  was  further  upraised,  of  which  the 
Rocky  Mountains  are  the  salient  ridges.  The  broad 
shallow  basin  of  the  Colorado  River  was  now  de- 
fined. On  the  Pacific  coast,  this  disturbance  was  felt 
only  in  the  defining  of  the  position  of  the  Coast 
Ranges. 

The  great  feature  of  this  post-Cretaceous  movement 
was  the  re-emergence  of  that  part  of  the  ancient  Cor- 
dilleran  area,  now  called  the  Plateau  Province.  It 
had  sunken,  with  the  whole  breadth  of  the  Cordil- 
leran  Land,  at  the  end  of  the  Eozoic  Mon.  Now  the 
two  limbs  of  the  American  continent  were  joined  to- 
America  gether.  From  Middle  California  to  Boston  Bay  was 
during  the  a  continuous  land  connection.  Only  a  narrow  border 
Camozoic.  remained  to  be  a(j<ied  around  the  Atlantic,  Pacific, 
and  Gulf  coasts.  Remnants,  however,  of  the  ancient 
Mediterranean  Sea  remained  in  the  interior,  forming 
lakes  as  large  as  Superior.  These  in  the  succeeding 
ages  were  at  times  enlarged,  at  times  contracted, 
through  the  orographic  movements  taking  place,  and 
finally  filled  or  drained  (see  Talks  XVIII.  and 
XLIV.).  During  the  Miocene  epoch  a  great  lake 
covered  the  region  of  the  Great  Plains,  as  far  as  the 
Gulf  of  Mexico — a  region  which  appears  to  have 
been  mostly  land  during  the  Eocene.  Meantime, 


The  Throes  of  the  Continent. 


vast  volcanic  eruptions  were  taking  place  along  the 
Pacific  border,  burying  thousands  of  square  miles 
under  lava,  and  supplying  ashes  which  filled  some  of 
the  western  lakes  four  thousand  feet  deep. 

The  interior  lake  history  continued  of  similar  tenor 
till  the  close  of  the  Pliocene,  when  the  grand  move- 
ments occurred  which  impressed  on  the  broad  Cor- 
dilleran  region  its  present  surface  features.  The 
rocky  sheets  of  the  Great  Plains  were  tilted  into  a 
position  which  secured  drainage  of  the  great  lake 
which  had  covered  them.  In  the  far  west,  the  Sierra 
Nevada  and  the  Wahsatch  were  rent  longitudinally 
by  great  faults  along  their  crests,  and  the  continental 
mass  between  the  faults  sank  down  one  or  two  thou- 
sand feet,  forming  the  Great  Basin,  and  returning  it 
to  the  depressed  condition  which  it  had  held  through 
the  whole  of  Palaeozoic  time.  On  its  eastern  and 
western  borders  gathered  two  lakes,  each  as  large  as 
Huron,  the  eastern  of  which  has  shrunken  to  Great 
Salt  Lake,  Utah,  and  Sevier  ;  while  the  western  ex- 
ists only  in  the  remnants  known  as  Pyramid,  Win- 
nemuca,  Carson,  Walker,  and  Humboldt  lakes. 
Later  mountain  ranges  have  risen  here  and  there  in 
the  Basin,  and  volcanic  outbursts  have  contributed 
to  diversify  the  topography.  These  final  disturb- 
ances, followed  probably  by  some  later  ones— all  em- 
braced within  the  Quaternary  period— shattered  the 
Plateau  Province  to  a  destructive  extent.  Great  frac- 
tures ran  through  it  from  end  to  end.  On  one  side 
of  each,  the  rocky  sheet  is  generally  upraised,  and  on 
the  other,  depressed.  Volcanic  mountains  have  been 
built  up  here  and  there,  and  earthquakes  have  shat- 
tered the  blocks  shaped  by  the  meridional  faults. 


324      Walks  and  Talks  in  the  Geological  Field. 

Simultaneously,  surface  erosions  have  perpetually 
changed  the  configuration  of  the  surface.  Eivers 
have  cut  their  way  through  mountains,  through  lava 
plains,  through  the  later  strata,  and  in  some  cases,  a 
thousand  feet  into  the  long-buried  formations  of  the 
primitive  Cordilleran  Land. 


XLVII.     THE  BEIGN  OF  ICE. 

CONTINENTAL    GLACIATION. 

Teleolog-        THE  gradual  advancement  of  organic  improvement 
icaiargu-   ^ad  now  reached  a  stage  where  the  next  step  must 

naent  re- 
garding     bring   man   upon    the    theater   of  life.     Even    the 

the  Glacial  an  jmais  which  man  was  destined  to  domesticate  were 
Period. 

already  on  the  earth,  and  awaiting  the  advent  of 

their  master.  The  forests  too,  had  assumed  the 
aspect  which  was  to  become  familiar  to  man,  and 
seemed  to  stand  expectant  of  the  being  so  long  prom- 
ised. 

But  nature  must  yet  pause.  The  continents  in- 
tended for  civilized  man  lack  something  yet  to  fit 
them  for  his  advent.  Throughout  Asia,  Europe,  and 
North  America,  the  continental  surface  had  become 
deteriorated  by  erosions  and  wastage  taking  place 
during  the  reign  of  mammals.  The  land  had  been 
set  apart  for  the  use  and  convenience  of  this  dynasty, 
and  in  their  service  it  had  been  exhausted.  Each  of 
the  great  dominant  dynasties  in  succession,  had  the 
continents  for  their  use,  and  in  their  behoof  they 
were  worn  out.  For  each  new  dynasty  a  renovation 
was  demanded.  At  the  present  juncture,  the  soils 
had  been  reduced  through  wastage,  to  the  condition 


GLACIALLY  FACETED  AND  SCRATCHED  PEBBLE, 

Two  sides  of  which  are  shown.    This  specimen  bears  eighteen  facets.   They 

indicate  successive  positions  of  the  pebble  in  the  ice,  in 

which  it  was  set  like  a  diamond. 


326     Walks  and  Talks  in  the  Geological  Meld. 

which  we  plainly  see  approaching  again  under  the 
actions  exerted  during  the  human  reign.  The  rivers, 
long  confined  to  the  same  channels,  had  excavated 
deep  gorges.  Eetired  in  these  their  evaporation  was 
checked,  the  clouds  were  starved,  and  the  soils  were 
robbed  of  their  rains.  Every  tributary  had  scored  a 
ravine  which  split  the  land.  The  streams  were 
inaccessible  and  dwarfed,  and  their  availability  for 
human  uses  seriously  impaired.  There  must  be  a 
general  repair  of  the  surface  before  it  would  meet  the 
demands  of  a  being  of  such  enterprise  and  resources 
as  man  was  destined  to  be. 

The  end  so  necessary  was  accomplished  without  de- 
parture from  the  fundamental  method  of  all  the 
previous  history  of  the  continents.  Uplift  and  subsi- 
dence accomplished  the  glacial  renovation  which 
now  approached.  We  have  already  studied  many 
indications  of  glacier  action.  We  have  concluded 
(Talk  III.,  which  should  now  be  reviewed)  from  the 
inductive  evidence,  that  a  continental  glacier  has 
some  time,  brooded  over  the  land,  and  we  have  made 
some  observations  on  actual  glaciers  (Talk  IV.). 
Gradual  The  mild  climate  of  the  middle  and  later  Tertiary 

lowering    time  wkich  ha(j  prevailed  as  far  north  as  Disco,  on 
of  temper- 
ature,        the  coast  of  Greenland,  and  Melville  and  Bennett 

Islands  in  the  Arctic  Ocean,  had  already  been  suc- 
ceeded by  a  colder  one.    The  cause  of  the  change 
remains  an  unsolved  problem.     The  later  invasion  of 
Causes  of  severe  cold  throughout  the  northern  temperate  zone 
faTeo10n:  is  generallv  ascribed  to  northern  elevation  ;  but  there 
graphical,  is  much  reason  to  suppose  it  the  result  of  certain 

(6)  astro-     agronomical  changes,  and  to  hold,  also,  that  this  was 
nomical. 

but  one  of  a  succession  of  glacial  visitations.     What- 


The  Reign  of  Ice.  327 

ever  the  cause,  the  reality  of  the  glacier  period  can 
not  be  questioned.  The  area  of  perpetual  snow  had 
extended  its  limits  from  the  arctic  zone  into  northern 
America.  In  the  middle  latitudes,  an  unwonted 
chill  was  already  experienced  in  the  atmosphere. 
Successive  winters  grew  more  and  more  severe,  and 
the  snow  lingered  always  later  in  the  spring.  There 
were  deep  ravines  where  it  survived  the  summer. 
With  continued  depression  of  mean  temperature,  the 
winter  snows  still  further  delayed  their  departure. 
The  forest  was  changed.  One  by  one,  the  species 
suited  to  a  milder  climate  perished  ;  and  frost  began 
to  brown  foliage  in  a  zone  which  had  witnessed  a 
state  of  perpetual  verdure.  Year  by  year,  the  line  of 
permanent  snow  extended  itself  southward.  Proba-  nentsnow- 
bly  the  volume  of  snowy  precipitation  was  increased,  fhe^i^x" 
and  thus  the  march  of  the  reign  of  snow  was  accel- 
erated. 

The  sheet  of  perpetual  snow,  to  whatever  limit  it  Its  pas. 
reached,  was  divided  into  two  areas  by  an  isothermal  sage  into 
line.  Had  the  sun  never  exerted  a  thawing  influ- 
ence— had  no  thawing  ever  taken  place  in  any  por- 
tion of  the  snow,  it  would  have  remained  a  soft  and 
fleecy  covering.  But  wherever  incipient  thawing 
was  felt,  the  snow  crystals  began  to  resolve  them- 
selves into  grains  of  ice.  Down  to  the  latitude  where 
this  change  was  unable  to  proceed  farther,  the  con- 
dition of  the  snow  remained  granular,  as  it  now  does 
in  the  Alps.  If,  however,  the  melting  influence  pro- 
ceeded farther,  the  granular  snow-mass  resolved 
itself  into  solid  ice.  These  changes  can  be  traced  in 
the  snow  which  falls  upon  our  streets.  Thus  all  the 
southern  portion  of  the  snow-field  became  a  true 


328      Walks  and  Talks  in  the  Geological  Meld. 

glacier  ;  north  of  that  was  a  zone  of  neve;  and  possi- 
bly a  zone  of  soft  snow  covered  the  area  still  nearer 
the  pole.  All  this,  of  course,  supposes  precipitation 
to  have  taken  place.  If  in  any  region  precipitation 
was  wanting  or  scant,  the  snowy  or  icy  covering  did 
not  appear. 

Movement  On  its  northern  border,  the  glacier  was  fixed  to  the 
of  the  mass  of  ice  or  neve  beyond ;  and  very  probably  it 
was  fixed  to  the  earth.  The  glacier,  like  all  glaciers, 
must  move ;  and  the  motion  would  be  developed 
along  the  free  border.  The  glacier,  therefore,  trav- 
eled southward.  Consider  the  consequences  of  the 
motion.  The  soft  snow  had  filled  the  gorges  and  the 
river  valleys.  It  had  settled  around  cliff  and  crag, 
and  when  it  became  ice,  it  held  them  in  its  firm 
grasp.  The  motion  of  the  glacier  wrenched  frag- 
ments from  their  fastenings  and  moved  them  south- 
ward. The  rock  fragments,  like  diamonds  in  a 
setting,  marked  and  scored  the  underlying  surface. 
The  loose  materials,  the  accumulation  of  a  previous 
geologic  seon,  were  plowed  to  the  bed-rock.  The  bed- 
rock was  scored  and  striated  by  the  tremendous 
power  of  the  glacier. 

its  (level-       Every  year,  the  great  ice-sheet  encroached  a  little 
opment      farther  on  the  unglaciated  area.    This  resulted  partly 
ward.         from  the  southward  growth  of  the  glacier,  and  partly 
from  its  southward  motion.     In  its  motion,  it  pros- 
trated the  standing  forest,  and  the  ruins  were  min- 
gled with  the  rock-ruin  which  the  ice-mass  stirred 
and  transported.    The  march  of  the  glacier's  southern 
border  continued  until  it  reached  New  York,  Louis- 
ville, St.  Louis,  and  Topeka.    It  passed  over  Long 
Island  Sound  and  reached  the  ocean  shore.    West- 


330      Walks  and  Talks  in  the  Geological  Field. 

ward,  over  the  Great  Plains,  its  footmarks  are  not 
traced.  Perhaps  the  precipitation  there  was  insuffi- 
cient to  enable  the  snow  to  outlast  the  summer  heat. 
Further  west,  the  glaciation  seems  to  have  been  re- 
stricted to  mountain  ranges.  But  glaciation  was  far 
from  unknown,  even  to  the  Pacific  slope.  North- 
ward, the  extent  of  the  glaciation  increased,  as  far  as 
Alaska. 

An  "open"     Now  the    geologic   winter    was    marked    by    an 
spell.          c<  open  M  spell>    It  probably  lasted  for  centuries.    The 
ice  dissolved,  and  the  border  of  the  glacier  retreated 
Inter-         perhaps,  to  the  latitude  of  Marquette.      Over  the  un- 
giaciai        covered  area,  it  was  a  new  spring  time.    Vegetation 
sprang  into  existence,  and  a  fresh  soil  accumulated. 
Then  came  a  recurrence  of  cold.     The  old  glacier  re- 
Recur-       sumed  its  southward  movement.      In  saying  it  was  a 

renceof      "continental"  glacier,  it  is  not  meant  that  an  ice- 
cold. 

field  continent-wide  moved  with    a    consentaneous 

movement.  The  ice-sheet  felt  the  influence  of  the 
underlying  topography.  Its  motion  tended  every- 
where to  the  lower  level  and  warmer  situation.  Sel- 
Theborderdom  was  that  direction  precisely  south.  In  the  val- 
of  the  ley  of  the  Connecticut,  the  movement  was  south.  In 
the  valley  of  the  Mohawk  it  was  eastward.  Through 
the  valley  now  occupied  by  Lakes  Ontario  and  Erie, 
it  was  southwest  as  far  as  Indianapolis,  and  south  as 
far  as  Columbus.  Another  glacier  stream  flowed 
through  the  valley  destined  to  be  the  basins  of  Lake 
Huron  and  Saginaw  Bay.  Its  southern  border  joined 
the  Lake  Erie  glacier  ;  and  the  long  broken  chain 
of  sand  and  bowlder  hills  passing  through  Ann 
Arbor,  shows  where  the  joint  rubbish  of  the  two 
glaciers  was  left.  Another  glacier  stream  passed 


332      Walks  and  Talks  in  the  Geological  Meld. 

along  the  valley  of  Lake  Michigan  ;  another  down 
the  valley  of  Green  Bay  and  its  continuation  to 
Madison.  Still  others  streamed  from  Keweenaw 
Point  and  Duluth  into  central  Wisconsin  and  Min- 
nesota. Wherever  these  local  ice-streams  termi- 
nated, they  left  moraines  to  mark  the  extent  of  their 
advance.  This  was  the  "second  glacial  period." 
The  entire  continent  north  of  an  irregular  line  pass- 
ing through  New  York,  Fort  Wayne,  Madison,  Min- 
neapolis, and  Yankton,  lay,  like  the  soil  of  Green- 
land in  our  time,  buried  beneath  a  bed  of  ice  and 
snow  some  thousands  of  feet  thick.  The  summits  of 
the  Adirondacks,  the  Catskills,  and  the  White 
Mountains  barely  emerged  above  the  desolate,  feat- 
ureless waste. 

The  fate  of  During  this  reign  of  ice,  the  snows  fell  which  over- 
the  mam-  took  the  long-haired  elephant  of  Siberia  and  Alaska 
Siberia?  (Talk  XXVH.),  and  buried  them  in  herds.  They  had 
been  browsing  for  many  generations  on  that  north- 
ern slope.  I  know  not  to  how  severe  a  climate  their 
natures  fitted  them  ;  but  clearly  it  had  not  been  a 
climate  which  brought  perpetual  snow.  Now  they 
experienced  a  new  chill  in  the  atmosphere.  Now 
the  snows  descended  and  they  crowded  themselves 
together  in  ravines  for  warmth  and  mutual  protec- 
tion. Their  instincts  taught  them  this  mode  of  self- 
preservation.  They  had  often  outlived  a  snow-burial 
during  winters  preceding.  But  their  last  burial 
finally  arrived.  Now  no  thaw  succeeded  the  over- 
whelming storrn.  No  spring-time  returned  to  release 
them  from  their  chilly  retreat.  Spring  only  turned 
the  snowy  blanket  to  ice.  Other  winters  buried  the 
mammoth  beneath  added  beds  of  ice.  In  such 


A  Geologic  Spring  Time.  333 

.a  tomb,  they  lay  unchanged  until  the  age  of  man 
and  slowly  returning  warmth  brought  their  lifeless 
carcasses  to  a  dumb  resurrection. 

The  accumulation  of  five  thousand  feet  of  ice  over  Results 
a  portion  of  the  earth's  surface  required  some  new  ofthe 
adjustments  of  equilibrium.      If  the  ice-bed  covered  giaciaiice: 
the  entire  north,  and  the  terrestrial  crust  remained 
rigid,  the  added  weight  transferred  the  earth's  center 
of  gravity  toward  the  north,  and  with  it  flowed  the 
ocean  northward.    With  a  flooding  of  all  the  north- 
ern shores  there  was  a  corresponding  emergence  of 
the  antarctic.    If  the  weight  of  ice  depressed  the  ter-  .floodlng 
restrial  crust,  the  position  of  the  center  of  gravity 
may   not  have  been  changed ;  but  the  shores  de- 
pressed would  be  flooded  by  the  ocean,  as  before. 
Farther,  the  displaced  fluid  matter  beneath  sought 
escape,  through  fissures,  to  the  surface.    If  the  enor- 
mous ice-pressure  was  felt  by  the  regions  east  of  the 
Great  Plains  and  north  of  the  Snake  Elver,  the  de- 
pression of  the  glaciated  regions  caused  the  fluid  in- 
ternal substances  to   react  beneath  regions  farther  ism. 
west  and  south  ;  and  in  many  cases,  to  develop  frac- 
tures through  which  molten  outflows  took  place.     In 
this  view,  the  great  post-pliocene  lava  floods  of  the 
west  were  the  counterpart  of  the  great  ice-burdens 
of  the  east  and  north. 


XLYIII.    A  GEOLOGIC  SPRING  TIME. 

INCIDENTS  OF  THE  CHAMPLAIN  EPOCH. 

THE  rigor  of  the  long  winter  began  to  relent.     We 
can    not   certainly    state    what  physical  conditions 


334      Walks  and  Talks  in  the  Geological  Meld. 

Evidence    brought  about  the  change ;  but  if  elevation  brought 
of  sub-       the  cold,  then  probably,  the  return  of  warmth  re- 
sulted from  restoring  the  ancient  level.     We  are  cer- 
tain, on  good  evidence,  that  a  subsidence  took  place. 
At  some  time  after  the  advent  of  general  glaciation, 
the  eastern  United  States  and  Canada  were  inundated 
elevated     ^v  t^ie  ocean-    Tne  depth  of  the  submergence  was  470 
sea  feet  at  Montreal ;  and  it  diminished  gradually  south- 

hes'  ward.  At  Lewiston,  Maine,  the  sea-beach  is  two 
hundred  feet  above  present  tide-level ;  near  Boston, 
one  hundred  feet ;  on  Naiitucket,  eighty-five  feet. 
Northward,  on  the  contrary,  the  submergence  in- 
creased in  depth.  On  the  coast  of  Labrador,  it  was 
five  hundred  feet ;  in  Barrows'  Strait  it  was  over  one 
thousand  feet.  The  usual  opinion  is  that  this 
submergence  occurred  after  the  dissolution  of  the 
glacier ;  but  I  incline  to  the  conviction  that  it  was 
coincident  with  the  glacier.  I  have  already  sug- 
gested, following  Croll  and  general  opinion,  that  a 
load  of  northern  ice  would  very  probably  cause  sub- 
mergence of  northern  shores — though  I  think  it  re- 
sulted from  depression  of  the  crust,  rather  than  a 
shifting  of  the  center  of  gravity.  Such  submergence 
would  be  greatest  northward.  The  facts  observed  seem 
to  show  that  it  was  a  submergence  of  the  glacial 
epoch,  instead  of  the  post-glacial.  If  the  sunken 
shores  were  already  buried  in  ice,  the  temperature  of 
the  sea  would  dissolve  it,  and  the  sea-bottom  would 
be  of  the  usual  character  of  a  submerged  beach. 

The  depths  of  submergence  just  mentioned  are  far 
less  than  would  have  taken  place,  if  the  crust  of 
earth  had  yielded  readily  to  the  pressure  of  five 
thousand  feet  of  ice.  To  have  influenced  the  tern- 


A  Geologic  Spring  Time.  335 

perature,  there  must  have  been  a  much  greater-  sub- 
sidence from  the  point  of  maximum  elevation.  It  is 
reasonable  to  conclude  that  the  action  which  caused 
the  original  elevation  was  now  reversed,  and  much 
greater  subsidence  took  place  than  was  due  to  the 
load  of  ice. 

Whatever  the  amount  of  subsidence  ;  whatever  its  >pne  mei^ 
cause  ;  whatever  the  cause  of  the  climatic  ameliora-  ing  of  the 
tion,  there   is  no  question  about  the  return    of  a 
geological  spring.    The  glacier  began  to  waste  more 
than  its  annual  growth.    A  steady  recession  began 
along    its  southern  margin.     A  series  of  morainic 
loops  was  left  to  mark  its  farthest  advance.    They 
were  composed  of  bowlders  and  sand.    The  materials  Terminal 
were  accumulated  in  hills  and  ridges,  with  interven-  moraines- 
ing  "pot-holes  "  and  valleys.    The  dissolution  of  the 
ice-field  proceeded  with  rapidity.    Lively  rills  flowed 
over  the  surface  of  the  ice,  and  turbid  streams  sprang 
from  Ihe  foot  of  the  glacier — such  streams  as  make 
the  Aar  (Talk  VIII.)  and  the  Arve  (Talk  IV.).    The 
moraine  deposits  were  partially  washed  away.     The 
moraine  of  the  first  glacial  epoch,  farther  south,  was 
now  subjected  to  the  action  of  a  second  flood.    It  suf-  The  out,er 
fered  greater  erosion  than  the  second  moraine,  and  moraine 
hence  remains  to  us  a  less  conspicuous  feature  than 
the  second. 

The  ice-sheet  had  laid  down  an  unstratified  bed  of  Material 
"till" — a  compact  mass  of  clay,  pebbles,  and  bowl-  trans- 
ders  ;  the  glacial  flood  transported  vast  quantities  of 
materials,  and  left  them  in  a  state  of  torrential  strati-  beyond 
fication  overspreading  the  till.    There  is  much  rea-  a{ 
son  to  believe  that  the   materials  thus  transported 
were  borne  beyond  the  limits  reached  by  the  glacier. 


336      Walks  and  Talks  in  the  Geological  Meld. 

In  this  way,  the  action  of  the  glacial  expedient  for 
renovating  the  surface  of  the  north  was  extended  to 
the  southern  states.  There  has  certainly  been  a 
southward  transportation  of  pebbles  and  sand 
throughout  all  the  Gulf  States.  -It  was  an  event 
synchronous  with  the  dissolution  of  the  great  gla- 
cier. But  we  must  bear  in  mind  that  the  south  had  not 
been  visited  by  an  agency  which  plowed  up  the  dis- 
integrated rocks  accumulated  during  preglacial  ages. 
The  flooding  of  the  south  exerted  only  a  surface  action. 
Present  Between  the  glacier  and  the  floods,  the  surface  of 

drainage    the  wnoie  country  east  of  the  Great  Plains— with  the 
systems  es- 
tablished, exception  of  a  few  small  isolated  areas — underwent  a 

process  of  thorough  repair.  The  sharp  river  gorges 
were  filled — even  an  ancient  gorge  of  the  Niagara 
Eiver— and  a  fresh  bed  of  subsoil  materials  was 
spread  over  the  land.  The  larger  rivers  sought  out 
the  drainage  valleys  which  they  had  occupied  before 
the  invasion  of  glaciers.  The  fundamental  features 
of  the  drainage  were  everywhere  determined  by  the 
underlying  rocky  structure.  But  many  of  the 
smaller  streams  which  now  sprang  into  existence, 
selected  for  the  first  time  their  winding  channels 
among  the  inequalities  of  the  Drift-covered  surface. 
From  that  epoch  to  the  present,  all  the  streams  have 
employed  themselves  in  effecting  an  ever  deepening 
erosion.  Of  the  greater  arteries  of  the  continental 
drainage,  the  ancient  preglacial  bounding  walls  may 
sometimes  still  be  traced.  The  high  cliffs  of  the 
Upper  Mississippi  show  where  the  great  river  was 
bounded  throughout  all  Csenozoic  and  Mesozoic  time. 
There  was  an  epoch  when  the  excavation  of  this 
gorge  began.  The  great  tide  swept  along  at  the  high 


A  Geologic  Spring  Time.  337 

level  of  the  land.  But  the  stream  has  also  scored 
deeper  than  at  present.  The  rocky  bottom  of  its 
channel  is  everywhere  many  feet  below  the  present 
bed  of  sediment.  The  country  stood  higher  once 
than  now ;  the  descent  to  the  sea  was  sharper,  and 
the  erosion  more  profound. 

Of  course,  during  the  melting  epoch  of  the  great  Flooded 
glacier,  all  the  streams  were  flooded.  Not  only  did  rivers  left 
the  dissolving  ice  supply  enormous  quantities  of tel 
water ;  evaporation  must  have  been  increased  by  the 
extension  of  evaporating  surface,  and  condensation 
must  have  been  promoted  by  the  large  amount  of 
ice-cold  surface.  It  was  an  epoch  of  rains  and  floods. 
All  the  rivers  have  left  records  of  their  ancient  alti- 
tudes. These  are  the  terraces.  On  the  Connecticut 
we  find  them  from  one  hundred  and  eighty  to  two 
hundred  feet  above  present  flood  level ;  on  the  Hud- 
son and  Mohawk,  three  hundred  and  thirty  feet ;  on 
the  Genesee,  two  hundred  and  thirty-five  feet ;  on 
the  lower  Ohio,  fifty  to  one  hundred  and  eighty  feet ; 
on  the  Missouri,  two  hundred  and  fifty  feet ;  and  so 
throughout  North  America,  all  the  rivers  at  this 
epoch  were  flooded. 

The  Niagara  River  had  been  at  work  on  a  vast  The  Niag. 
gorge  ever  since  the  Devonian  Age.    Probably  none  ara  s°rse 
of  the  Great  Lakes  except  Superior,  then  existed.  Glacial 
From  Lake  Superior  sprang  a  river  which  flowed  Period, 
along  a  valley  in  which  the  basins  of  Lake  Huron 
and  Lake  Erie  have  since  been  excavated.     At  a 
point  west  of  the  present  mouth  of  the  Niagara,  it 
made  a  fall,  and  flowed  as  a  river  along  the  Ontario 
valley,  and  thus  to  the  sea.    In  the  course  of  ages, 
the  stream  excavated  a  gorge  as  far  as  the  whirlpool 


338      Walks  and  Talks  in  the  Geological  Field. 

— perhaps  even  farther.  On  the  re-establishment  of 
the  river,  it  did  not  find  its  ancient  gorge,  but  pre- 
cipitated itself  over  the  escarpment  at  Lewiston. 
Here  it  began  a  new  gorge,  and  dug  back  four  miles, 
when  it  struck  the  old  gorge.  Of  course  the  falls 
now  continued  their  recession  rapidly  as  far  back  as 
the  head  of  the  old  gorge.  Since  that  was  reached, 
the  work  has  been  continued  in  solid  rock,  and  is  now 
proceeding  at  the  rate  of  three  feet  a  year. 
Question  The  question  has  been  much  discussed  whether  the 

of  the        basins  of  the  Great  Lakes  were  excavated  by  the 

basins  of 

the  Great    action  of  the  continental  glacier.     By  Ramsay,  lake 

Lakes.  basins  have  been  generally  attributed  to  such  action. 
By  others,  the  doctrine  is  held  in  light  esteem,  since 
we  have  evidence,  in  some  cases,  that  glaciers  have 
moved  over  sheets  of  clay  without  plowing  them  up. 
I  incline  to  agree  in  part  with  both.  The  positions 
of  the  terminal  and  lateral  moraines  show  that  gla- 
ciers moved  along  the  beds  of  Lakes  Erie,  Huron, 
and  Michigan,  and  Saginaw  and  Green  Bays.  What 
directed  ice-streams  to  these  positions  ?  A  pre-exist- 
ing valley.  What  caused  the  valley?  The  erosion 
of  the  great  river  which  had  been  flowing  out  of 
Lake  Superior  during  Mesozoic  and  Csenozoic  ages. 
The  valley  may  have  been  a  mile,  or  five  miles,  wide, 
and  bounded  by  precipitous  rocky  walls.  When  the 
glacier  commenced  its  movement  along  such  a  valley, 
it  exerted  powerful  erosion  along  the  steep  bounding 
walls,  and  wore  them  down  to  the  gentle  slopes 
which  now  form  part  of  the  bed  of  the  lake.  The 
basins  of  the  lakes  are  demonstrably  works  of  erosion. 
Why  the  great  glaciers  worked  there  more  than  else- 
where, was  because  the  great  river  had  inaugurated 


A  Geologic  Spring  Time. 


the  work  and  invited  the  glacier.  A  glacier  also 
moved  out  of  the  western  end  of  Lake  Superior.  A 
valley  already  existed  —  indeed  a  lake  basin  existed, 
shaped  by  the  ancient  upheaval  of  rocks  along  the 
northern  and  southern  shores. 

In  regions  where  returning  spring-time  found  the  Glaciai 
general  surface  nearly  level,  and  locally  indented  lakes  of 
with  basin-like  depressions,  the  Champlain  floods 


formed  large  numbers  of  lakes  and  lakelets.  Such  Minne- 
depressions  might  arise  from  the  rocky  configuration  sota>  etc< 
of  the  country  —  especially  the  larger  depressions. 
More  generally  they  were  mere  intervals  inclosed  by 
hills  and  ridges  of  Drift.  Thus  arose  the  numerous 
lakes  of  Maine,  Michigan,  and  Minnesota.  When- 
ever a  lakelet  found  an  outlet,  the  process  of  erosion 
began  ;  the  lakelet  was  continually  lowered,  and  in 
many  cases,  it  has  been  completely  drained.  In  all 
cases,  the  filling  of  the  lakelets  has  gone  forward  in 
the  manner  described  in  Talk  VIII.  Nature  is  finish- 
ing the  world  before  our  eyes. 

It  was  during  the  spring-time  empire  of  water,  that  The  mak. 
the  Great  Lakes  stood  at  the  high  levels  described  in  ing  of  the 
Talk  VII.    To  this  inundation  of  Illinois,  the  prairies  prairies' 
of  the   Mississippi   owe   their   origin.    The  prairie 
formation  is  a  stratified  deposit  of  fine  clay,  sand,  and 
alluvial  matter.    It  is  a  fresh-water  deposit.    It  was 
laid  down  on  the  top  of  the  Drift.    The  topographical 
and  geological  facts  point  to  the  great  lacustrine  flood 
as  the  occasion.    When,  in  the  course  of  time,  the 
high  waters  subsided,  the  lake  bottom  was  left  ex- 
posed.   It  lay  a  barren  waste  until  the  seeds  of  vege- 
tation were  distributed  over  it  by  natural  means. 
Birds  and  winds  were  the  principal  agents  ;  but  these 


340      Walks  and  Talks  in  the  Geological  Field. 

agents  transport  only  the  lighter  seeds — the  seeds  of 
grasses  and  herbs.  The  forest  was  standing  thrifty 
and  green  around  the  border  of  the  ancient  lake,  but 
its  seeds  found  little  opportunity  to  gain  foothold  on 
the  old  lake-bottom.  The  Indian  was  here.  He  had 
paddled  his  canoe  in  the  waters  above  the  soil  which 
was  now  a  prairie.  When  the  grasses  and  herbs  had 
been  browned  by  the  first  frosts  of  Autumn,  the 
Indian's  torch  set  them  ablaze.  The  air  was  filled 
with  smoke  during  the  dry  and  sunny  days  which 
follow  the  killing  frosts.  The  west  wind  wafted  the 
smoke  to  New  England,  and  our  ancestors  said, 
"The  Indian  Summer  is  here."  But  the  burning 
killed  the  shoots  of  the  young  trees  without  injuring 
the  roots  of  the  grasses  and  sedges.  So  when  May 
Covered  the  surface  again  with  green,  the  grasses, 
were  the.re,  but  the  woody  shoot  was  dead.  Thus  the 
prairies  remained  treeless.  When  the  emigrant  dis- 
covered the  Indian  at  his  annual  burning,  he  said, 
"That  is  the  explanation  of  the  treelessness."  But 
he  never  explained  why  the  region  was  treeless 
enough  in  the  beginning  to  allow  the  surface  to  come 
into  possession  of  the  grasses,  and  furnish  the  Indian 
occasion  for  the  burning. 

For  recent  studies  and  fuller  statements  regarding  the  glacial 
period,  see  Professor  Chamberlin's  papers  in  recent  United 
States  Geological  Reports  and  Professor  Wright's  Ice  Age  in 
America  and  Man  and  the  Glacial  Period.  F.  S. 


XLIX.     THE  EARTH  EECEIVES  HER  KING. 

THE  ADVENT  OF   MAN. 

AT  SOME  juncture  in  the  progress  of  these  later 
events,  man  made  his  first  appearance  on  the  earth. 


The  Earth  receives  her  King.  341 

He  was  not  present  during  Tertiary  periods,  in  any 
portion  of  the  world  which  has  been  subjected  to 
research.  There  appears  to  have  been  no  European 
Tertiary  man,  and  no  American  Tertiary  man.  This 
conclusion  is  now  almost  universally  accepted. 
But  both  in  America  and  Europe,  man  seems  to  Man 

have  been  present  during  a  portion  of  the  Glacial  durinsthe 

Glacial 
Epoch.    American  man  dwelt  in  California.    Along  Epoch. 

the  Pacific  coast,  as  I  stated  in  Talk  XL VII.,  a 
milder  climate  prevented  the  prevalence  of  universal 
glaciers.  The  situation,  therefore,  may  have  been  as 
favorable  for  human  occupation  as  that  in  our  day,  at 
the  foot  of  the  glaciated  valleys  of  Switzerland.  The 
human  remains  of  California,  however,  are  found  in  Remains 
situations  which  at  first  excite  our  wonder  ;  for  they  in  Cal1- 
lie  in  the  deep  placers  underneath  great  tables  of 
ancient  lava  (Talk  XVI.,  end).  These  lava-sheets,  in 
the  judgment  of  Professor  J.  D.  Whitney,  were 
erupted  in  the  latter  part  of  the  Pliocene  Epoch  ;  and 
if  so,  man  was  a  Tertiary  resident  on  the  Pacific 
coast.  This  opinion,  I  have  myself  been  disposed, 
heretofore,  to  adopt.  (Preadamites,  pp.  426-428.) 
Everything  depends  on  the  epoch  of  the  lava  erup- 
tion. That  would  be  given,  if  the  other  fossil  re- 
mains of  the  deep  placers  afforded  unquestionable 
criteria  of  age.  Professor  Whitney  thinks  they  do. 
In  his  report  on  California,  he  says:  "The  beds  Age  of 
which  were  deposited  prior  to  the  great  volcanic  dis-  ^*^~ 
turbance  and  consequent  overflow  of  lava  throughout 
the  Sierra,  inclose  a  peculiar  fauna  which  we  refer  to 
the  Pliocene  Epoch,  and  which  appears  to  have  some 
analogy  with  the  group  of  the  same  age  occuring  on 
the  Niobrara  and  White  Rivers  and  in  their  vicinity, 


342      Walks  and  Talks  in  the  Geological  Field. 

to  the  east  of  the  Rocky  Mountain  chain."  "  Among 
the  animals  of  the  Pliocene  of  California,  or  the 
group  which  preceded  the  epoch  of  volcanic  activity, 
we  recognize  the  rhinoceros,  an  animal  allied  to  the 
hippopotamus,  an  extinct  species  of  horse,  and  a 
species  allied  to  the  camel  and  resembling  the  Meg-a- 
lo-me'-ryx  of  Leidy  ;  all  these  species,  so  far  as  we 
know,  are  peculiar  to  the  deposits  under  the  lava." 
As  to  the  plant  remains  found  in  the  same  beds,  Dr. 
Newberry  reports  that  they  are  not  older  than  the 
Miocene,  and  most  resemble  species  found  in  the 
later  European  Tertiaries.  For  myself,  I  hardly 
think  this  evidence  is  fully  conclusive  on  the  Pliocene 
age  of  the  deep  placer  gravels  with  human  relics.  I 
feel  persuaded  that  the  great  lava  eruption  was  con- 
nected with  the  enormous  load  of  ice  which  once 
covered  the  regions  farther  north  and  east ;  and  if  so, 
they  occurred  probably  while  the  Glacial  Epoch  was 
at  its  meridian.  Mr.  Boyd  Dawkins  thinks  the  evi- 
dence of  Pliocene  man  in  California  is  "unsatisfac- 
tory," because  almost  no  species  of  Pliocene  mam- 
mals have  survived  to  the  present,  and  the  strong 
presumption  is  afforded  that  man  is  not  an  exception. 
But  in  any  event,  American  man  existed  in  the 
Glacial  Epoch — not,  of  course,  in  the  midst  of  a  con- 
tinental glacier  ;  but  in  some  favorable  region  which 
glaciation  did  not  reach.  Much  of  the  "far  west" 
was  suitable  for  human  occupation  at  the  time. 
Great  lakes  existed  in  Oregon,  in  Utah,  and  Nevada  ; 
and  they  were  populated  by  a  molluscan  fauna  not 
less  exacting  in  its  requirements  than  the  types 
accompanying  man  in  the  present  epoch.  In  eastern 
America,  also,  some  human  relics  have  been  found 


The  Earth  receives  her  King.  343 

which,  as  is  thought,  argue  the  presence  of  man  in 
the  Glacial  Epoch.    Dr.  C.  C.  Abbot  has  described  Remains 
some  stone  implements  in  ancient  gravel  near  Tren-  from 
ton,  New  Jersey,1  and  the  announcement  of  Glacial  gravels. 
man  has  been  proclaimed ;  but  I  agree  with  Mr.  H. 
C.  Lewis,  that  these  gravels  are  post-glacial.    Strati- 
fied gravels  of  the  Drift  belong  to  the  epoch  of  the 
Champlain  floods.  The  deposits  of  the  Glacial  Epoch, 
with  local  exceptions,  are  unstratifled,  and  in  the 
nature  of  "  till."    The  Trenton  gravel  appears  to  be  a 
river-drift  deposited  during  the  flooded  stage  of  the 
Delaware. 

Human    implements    in    river-drift    gravels    are  Relics 
widely  known  in  Europe.     They  occur   especially  from  river 
along  the   valleys  of  the    Somme,  the    Seine,  the  Europe; 
Thames  —  but  also,  in  many  other  regions.     They 
have  been  the  subject  of  voluminous  discussion.      In 
Brazil,  stone   implements    have   recently  been    de- 
scribed in  large  numbers  from  the    gravels  of  the 
province  Rio  Gran-de  do  Sul.    From  caverns  many 
relics  have  been  obtained,  which  throw  much  light 
on  the  condition  and  associations  of  primitive  men. 
Numerous  other  facts  have  been  yielded  from  the  bot- 
toms of  European  lakes.    It  appears  that  the  early  LaAer 
inhabitants  constructed  their  habitations  on  piles  in  relics  from 
the  lakes,  and  communication  with  the  shore  was 
effected  by  a  bridge  which  could  be  readily  removed. 
Some  of  these  piles  still  remain.    Naturally,  many 
articles  used  by  the  dwellers  in  these  abodes  were  lost 
in  the  water  and  never  recovered.     Many  thousands 
have  been  dredged  up  in  recent  times.       Another 

i  A  vigorous  controversy  is  in  progress  regarding  the  antiquity 
of  these  relics.    F.  S. 


344      Walks  and  Talks  in  the  Geological  Meld. 

source  of  light  on  primitive  mail  is  found  in  the  sea- 
side accumulations  of  kitchen-refuse—piles  of  shells 
and  bones  and  organic  dSbris  reaching  several  yards 
in  length,  and  sometimes  eight  or  ten  feet  high. 
These  are  the  refuse  of  fishing  villages.  They  con- 
tain implements,  domestic  utensils,  and  personal 
from  Dan-  ornaments  once  belonging  to  the  inhabitants.  The 
ish  bogs,  peat  bogs  of  Denmark  and  other  countries  give  us 
other  relics.  From  the  mounds  and  other  burial 
places  much  further  information  is  obtained. 

Among  the  relics  of  these  early  settlers  in  Europe, 
of  relics  we  find  many  stone  axes— some  rough  and  others 
found.  laboriously  polished.  Flint  arrow-heads  and  lance- 
heads  are  very  common.  Fish-hooks  and  other  ar- 
ticles of  bone  occur  in  the  lakes  and  the  shell- 
mounds.  Very  numerous  articles  of  bronze  used  for 
ornament  are  dredged  from  the  lakes— brooches, 
bracelets,  pins.  Fragments  of  pottery  occur  in  the 
lakes  and  shell-mounds.  Woven  cloth  has  been  ex- 
humed from  some  of  the  oldest  deposits  ;  and  jars  of 
dried  apples  and  wheat,  and  even  cakes,  have  been 
yielded  from  the  pile-habitations.  The  older  relics 
are  rudest,  as  might  be  expected,  and  consist  exclu- 
Tne"a  es"sive^  °^  s^one  an(*  bone.  Later,  bronze  came  into 
of  prehis-  use,  and  the  workmanship  was  finer.  Lastly  iron  be- 
came  known.  Archaeologists  accordingly  divide  pre- 
historic time  into  three  ages :  1.  The  AGE  OF 
STONE  ;  which  was  subdivided  into  the  Palceolithic 
or  rough-stone  epoch,  and  the  Neolithic  or  polished - 
stone  epoch  ;  2.  The  AGE  OF  BRONZE  ;  and  3,  the 
AGE  OF  IRON.  Within  certain  geographical  limits 
these  three  ages  in  the  progress  of  culture  are  con- 
secutive. But  it  must  not  be  supposed  that  they 


The  Earth  receives  her  King.  345 

mark  periods  in  the  history  of  man  at  large.  The 
Age  of  Stone  is  long  past  in  Europe  ;  but  it  prevailed 
still  in  the  Hawaiian  Islands  when  discovered  by 
Captain  Cook  ;  and  still  prevails  among  some  Indians 
of  America. 

Gathering  together  the  numerous  facts  which  sup-  Man  in 
ply  information  concerning  the  primeval  inhabi-  ^^ 
tants  of  Europe,  we  are  able  to  set  the  following  in-  temporary 

ferences  in  order  :    When  man  first  made  his  advent  of  extinc* 

mammals. 

in  Europe,  that  continent  was  still  the  abode  of 
quadrupeds  now  long  extinct.  The  caverns  were 
shared  with  man  by  the  Cave  Bear,  the  Cave  Hyaena, 
and  the  Cave  Lion.  These  gradually  gave  place  to 
gigantic  Herbivores  —  the  Hairy  Mammoth,  the 
Hairy  Rhinoceros,  and  the  Reindeer.  The  Mam- 
moth roamed  in  herds  over  the  whole  of  Europe, 
Northern  Asia,  and  North  America  (Talk  XXVII.). 
The  Hairy,  or  Two-horned  Rhinoceros,  in  company 
with  another  two-horned  species,  thundered  through 
the  forests  or  wallowed  in  the  jungles  and  swamps. 
The  rivers  and  lakes  of  Southern  Europe  were 
tenanted  by  the  hippopotamus  and  the  beaver. 
Three  kinds  of  wild  oxen,  two  of  which  were  of 
colossal  strength,  and  one  of  these  was  "maned  and 
villous  like  the  Bonassus,"  grazed  with  the  marmot 
and  wild  goat  and  chamois  upon  the  hills  and  plains 
which  skirt  the  Mediterranean.  The  musk-ox  and 
the  reindeer  browsed  in  the  meadows  of  Perigord,  in 
the  south  of  France,  while  a  gigantic  elk  ranged  from 
Ireland  to  the  borders  of  Italy. 

From  similar  evidences,  we  learn  that  primitive  Also  in 
man  in  America  was  also  the  contemporary  of  quad-  America, 
rupeds  now  long  extinct.    Beneath  the  lava  of  Cal- 


346     Walks  and  Talks  in  the  Geological  Meld. 

ifornia,  the  bones  of  the  mammoth  and  mastodon 
and  the  broad-faced  ox  lie  mingled  with  the  bones 
and  implements  of  man.  East  of  the  Rocky  Moun- 
tains, the  relics  of  the  ancient  proboscidians  have 
often  been  discovered  in  such  association  with  human 
relics  as  to  afford  strong  evidence  of  contempora- 
neity. On  the  banks  of  the  Ashley  River  in  South 
Carolina,  human  bones,  arrow-heads,  hatchets  and 
potsherds  are  found  mingled  with  bones  of  the  hog, 
the  horse,  the  mastodon,  and  extinct  gigantic  lizards. 
In  the  same  epoch  lived  the  wide-faced  bison,  the 
shrub-loving  tapir  and  a  gigantic  beaver,  and  a  num- 
ber of  gigantic  Edentates — wanderers  from  South 
America. 

Tb    .  If,  from  the  monuments  which  these   primitive 

acter  of  people  have  left  behind,  we  attempt  to  form  an  esti- 
ma™asVe  mate  of  their  physical,  intellectual,  and  moral  char- 
shown  by  acteristics,  we  become  at  once  convinced  that  in  their 
rellcs'  cranial  characters  they  were  equal  in  rank  to  the  av- 
erage races  of  modern  times.  Beyond  all  question, 
they  were  no  connecting  links  between  man  and 
lower  animals.  The  evidences  of  their  intelligence 
place  them  as  high  as  the  Esquimaux.  In  mechani- 
cal skill  they  were  equal  to  the  manufacture  of  a 
large  assortment  of  implements  of  stone  and  bone. 
Before  the  close  of  the  Stone  Age,  they  produced 
many  evidences  of  an  aesthetic  faculty.  They  pol- 
ished their  stone  axes,  and  worked  their  arrow  and 
lance  heads  after  more  elaborate  and  artistic  pat- 
terns. Their  pottery  began  to  receive  some  crude 
decorations.  They  carved  the  bone  and  horn  handles 
of  some  of  their  weapons.  They  engraved  on  slate, 
ivory,  and  bone  the  figures  of  familiar  animals  ;  and 


The  Earth  receives  her  King.  347 

among  these  portraits  are  sketches  of  the  hairy  ele- 
phant, furnishing  further  evidence  of  their  contem- 
poraneous possession  of  the  forest  and  the  plain. 
These  men,  also,  possessed  a  religious  nature.  There 
are  certain  emblems  and  objects  which,  by  general 
admission,  must  receive  a  religious  interpretation. 
The  care  bestowed  on  the  dead  evinces  a  belief  that 
even  after  death  they  retained  relations  of  love  and 
recognition.  They  sent  them  on  their  mysterious 
journey  with  such  offerings  and  supplies  as  should 
meet  their  necessities.  They  felt  the  notion  of  a  Su- 
preme Divinity  stirring  within  them.  A  little  later 
they  erected  altars  and  built  rude  temples.  The 
Stone  Folk  of  Europe  were  every  way  MEN. 

Who  were  they?  And  whence  did  they  come? 
Where  did  the  first  men  appear  ?  Who  was  Adam  ? 
Are  these  peoples  descended  from  Adam  ?  These  are 
interesting  questions  which  strike  us  at  this  point, 
and  are  worthy  of  study  ;  but  I  do  not  regard  it  ex- 
pedient to  enter  upon  them  at  the  present  time.  The 
reader  who  may  desire  to  see  what  can  be  said  about 
them,  may  consult  "  Preadamites  ;  or,  a  Demonstra- 
tion of  the  Existence  of  Men  before  Adam  "—a  work 
which  is  essentially  a  commentary  on  portions  of 
Genesis  and  a  vindication  of  Biblical  ethnography. 


INDEX. 


Aar,  torrent  of,  51. 

Abyss  of  the  ocean,  66 ;  receives  little 
sediment,  76. 

Acervularia,  223. 

Acids  in  the  air,  271. 

Adirondacks,  features  of,  132. 

JEtna.  Mount,  106  seq.;  eruptions  of, 
107. 

Agassiz  and  Drift,  13. 

Ages  of  Man,  344. 

Air-breathers  of  Coal  period,  216, 294. 

Alaskan  mammoth,  192. 

Amoeba,  245. 

Ampnibians,  reign  of,  84 ;  charac- 
ters of,  217 ;  diminution  of,  297 ;  a 
comprehensive  type,  309. 

Ant-eater,  Banded,  303. 

Anthracite,  185. 

Anticipation  in  organic  structures, 

Anticlinal  explained,  89,  90 ;  in  oil 

accumulation,  169. 
Aphanite,  44. 
Appalachian  region,  320. 
Appalachians,  origin  of,  295. 
Archseopteryx,  312. 
Archegosaurus,  297. 
Argillite,  44 ;  primitive,  272. 


Bowlder  clay,  19. 

Brachiopods.  232,  237,  281,  290. 

Brains  of  early  mammals,  305. 

Brandon  frozen  soil,  121. 

Brontotherium,  308. 

Brontozoiim,  298. 

Brown  coal,  187. 

Burns  gas  well,  178. 

Ceenozoic,  Great  System,  84  ;  Times, 

303  ;  mammals,  305. 
Caking  coal,  187. 

Calabrian  earthquakes,  126,  127.        ' 
Cambrian,   System,  83;   fossils,  234 

seq.;  rocks,  235,  236. 
Cannel  coal,  186  ;  formation  of,  295. 
Canons,  result  of  erosion,  62. 
Carbonic  acid,  In  the  air,  292  ;  re- 

moval of,  293. 
Carboniferous  System,  84  :  fossils,  214 


Artesian   w 


;  prii 
ells, 


117,  170;  bored  for 


Assortment  of  sediments,  52,  229. 

August  meteors,  256. 

Bad  Lands,  63 ;  fossils  of,  198,  seq.;  de- 
scription of,  198. 

Bar  of  Mississippi,  55. 

Basaltic  columns,  115. 

Basin  of  a  geyser,  97. 

Basin  Province,  320. 

Basins  of  Great  Lakes,  338. 

Beaches,  ancient,  of  lakes,  46 ;  of  sea 
shore,  334. 

Becker.  G.  F.,  on  Comstock  Lode,  151. 

Bedded,  thin  or  thick,  73. 

Belodon.  298. 

Bilateral  symmetry,  237. 

Birds,  reptilian,  302,  312,  313  ;  gene- 
alogy of,  314. 

Bituminous  coal,  186. 

Bog  iron  ore,  38, 154, 157. 

Bonanza  denned,  147. 

Bowlders    described,  11 ;    enormou 


ge, 
bi 


290. 


Carinate  birds,  314. 

Caspian  Sea  and  salt,  159  seq. 

Catskill  Mts.  described,  62. 

Caucasus,  buried  ice  in,  121. 

Caverns  for  human  homes,  346. 

Cement  of  teeth,  190. 

Centrifugal  tendencies,  261,  262. 

Centripetal  tendencies,  261. 

Cephalaspis,  286,  287. 

Cestraciont  sharks,  284,  286. 

Chalk.  208. 

Chambered  shells,  228,  290. 

Chamonix  glaciers,  27. 

Champlain  epoch,  333  seq. 

Cheirotherium,  219. 

Chimney  of  a  geyser,  97. 

Cincinnati  ,  geological  situation  of,  90. 

Classification  of  strata,  78,  82,  83. 

Clay  beds  in  the  Drift,  33,  34,  35. 

Clay  iron  stones,  158. 

Coal,  geology  of,  183  seq.,  290  ;  origin 

of,  183,  290. 

Coal  measures,  185;  fossils  of,  214,  seq.; 
Cretaceous  age,  213  ,  of  Jurassic 


age, 
oal 


300. 


Coal  period,  scenes  from,  290. 
Cobble-stones,  11. 

Coleridge,  on  Chamonix  glaciers,  28. 
Columnar  lava,  114. 
Comets,   253  ;    nature  of,   254  ;    not 
natives  of  our  system,  255. 


examples    of,  14;  most    abundant    Comprehensive  types,  305,  308  seq. 
northward,  16 ;  sources  of,  16, 17;  di-    Comstock  Lode,  heat  on,  120 ,  min 
rection  ot  transportation  of,  21,  23.  i     ing  on,  146 ;  geology  of,  146. 


350 


Index. 


Concretions  of  ore,  158. 

Condensation  of  first  water,  269. 

Cone  of  geyser,  99. 

Cone,  volcanic  origin  of,  110. 

Conglomerate,  41 ;  notable  examples 
of,  41;  Carboniferous,  292. 

Continent-building,  316  seq. 

Contraction  of  earth,  140, 274. 

Cooling  earth,  140, 249,  250,  265. 

Cope,  E.  D.,  on  fossil  mammals,  205, 
304;  on  reptiles,  213. 

Copper  as  a  bowlder,  16. 

Coral  animals,  282. 

Cordilleran  Land,  280,  283,  317 ;  subsi- 
dence of,  318,  319. 

Corniferous  fishes,  286. 

Coryphodon,  307. 

Cosiguina,  eruption  of,  109. 

Cosmic  dust,  68,  2o6. 

Cretaceous  mammal,  305. 

Crevasse,  the  Grand,  25. 

Crevasses,  Forbes  on,  29 ;  phenomena 
of,  29. 

Crinoids,  233,  282. 

Crinoids  in  deep  sea,  69. 

Crustaceans,  235. 

Crust  of  the  earth,  267  seq.;  rugged 
character  of  primitive,  267  ;  thick- 
ened by  sediments,  276 ;  melted  oft 
below,  276. 

Cycads,  296. 

Cystids,  233. 

Darkness  on  the  deep,  269. 

Day  after  primeval  darkness,  270. 

Dawson,  G.  M.,  on  bowlders,  14. 

Deep  sea,  66, 208. 

Degeneration  of  types,  305. 

Delamater  gas  well,  178. 

Deltas,  55. 

Deluge  of  Noah,  80, 81. 

Deposits  of  geysers,  99. 

DeSaussure  on  Mer  de  Glace,  29. 

Devonian  Age,  84;  strata,  220  seq.; 
fossils,  222  seq. 

Digitigrade,  306. 

Dinichthys.  225. 

Dinoceras,  307. 

Dinosaurs,  297,  811. 

Diorite,  44. 

Dip  of  strata,  90. 

Dolomite,  primitive,  272. 

Drift  defined,  17 ;  its  constitution,  18 ; 
its  uses,  18;  semi-stratified  condi- 
tion of,  19  ;  causes  of  same,  20 ;  a 
northern  phenomenon,  21 ;  soluble 
substances  in,  36. 

Drift  in  mining,  188. 

Dromatherium,  303,  305. 

Dyke  or  Dike  defined,  115. 

Earthquakes,  125;  motions  of,  126; 
waves  of,  126 ;  kinds  of,  126 ;  causes 
of,  foci  of,  129, 131 ;  connected  with 
action  of  springs,  132. 

Elasmobranchs,  284,  286. 

Environment  and  organism,  82  seq. 


Eozoic,  77,83;  thickness  of,  276,279; 
often  at  highest  levels,  92 ;  rocks, 
241,  278  ;  fossils,  243. 

Eozoon,  243,  280. 

Erosion,  treated,57 ;  the  source  of  sed- 
iments, 57;  wastes  the  land,  59; 
in  the  Catskills,  62  ;  in  Tennessee, 
63 ,  in  the  interior,  323 ;  by  glacier 
action,  330. 

Eruptions  of  Vesuvius,  105;  JEtna, 
106;  Cosiguina,  109;  Kilauea,  109  ; 
other  volcanoes.  109. 

Eureka  mining  district,  152. 

Evolution,  facts  bearing  on,  239. 

Faults  in  mountains,  323. 

Favosites,  224. 

Feldspar  described,  42, 43 ;  primitive, 

Fern  vegetation  in  coal,  184,  293. 

Fiery  seon,  247. 

Fire  damp,  173. 

Firehole  River,  97. 

Fire-mist,  250;  primordial,  251, 259, 265. 

Firn,  22. 328. 

Fishes,  in  deep  sea,  69 ;  reign  of,  84, 
220 ;  fossil,  220,  225,  226\  283 ;  lessons 
from,  288. 

Flint  implements,  343. 

Flood  from  glacier,  337. 

Foci  of  earthquakes,  131. 

Footprints  in  sandstone,  299. 

Foot-wall  in  mining,  146. 

Foraminifera,  244. 

Forbes  on  Alpine  glaciers,  29. 

Formation,  defined,  85;  the  oldest 
not  sedimentary,  87. 

Fossils,  78;  speculation  on,  79. 

Frumento,  Monte,  on  ./Etna,  107. 

Gangue  in  mining,  152. 

Ganocephala,  311. 

Ganoids,  284,  286 :  prophetic,  309, 310. 

Garden  of  the  gods,  63. 

Gardiner's  River,  scenery  of,  95. 

Gar  pikes,  288. 

Gas,  geology  of,  170, 173  seq.;  localities 
of,  173, 174, 175;  composition  of,  181; 
value  of,  181 ;  source  of,  182  ;  perma- 
nency of,  182. 

Gasteropods,  232,  239. 

Geological  history,  table  of,  85. 

Geology,  where  data  of  are  found,  7, 8. 

Geyserite,  97. 

Geysers  in  National  Park,  97  seq.;  in 
Iceland,  and  New  Zealand,  100;  ex- 
planation of,  102. 

Giantess  geyser,  98. 

Gilbert,  G.  K.,  on  laccolites,  116. 

Glacier  defined,  22;  movements  of, 
23,  30,  31. 

Glaciers  continental,  324  seq.;  inva- 
sion of,  326 ;  pressure  of  and  conse- 
quences, 333  ;  examples  of,  339. 
!  Glaciers  of  the  Alps,  description  of, 
|     24  ;  movements  of,  23,  30,  31 ;  former 
I     extension  of,  31,  32. 


Index. 


351 


Globigerina  ooze,  66 :  in  chalk,  207. 

Gneiss,  43 ;  syenitic,  44. 

Goniatites,  1*90. 

Gorge  of  Niagara,  336, 337. 

Gould,  S.  Baring,  on  geysers,  100. 

Grand  Crevasse,  25. 

Grand  Plateau,  25. 

Granite  described,  43 ;  "  Quincy,"  43 ; 
formation  of,  278. 

Granulite,  43. 

Great  Plains,  292,  319, 320,  336. 

Great  Salt  Lake,  320. 

Groups  of  strata,  87. 

Gypsum,  geology  of,  163. 

Hadrosaur,  301. 

Haematite,  155. 

Hanging  wall  in  mining,  146. 

Hard  waters,  36. 

Heat,  internal,  102,  118,  seq.,  247 ;  in 
artesian  wells,  119 ;  in  mines,  120, 
148 ;  in  tunnels,  119  ;  rate  of  increase 
of,  119, 120 ;  theories  of,  123 ;  in  deep- 
er rocks,  247. 

Hesperornis.314. 

Hitchcock,  C.  H.,  on  bowlders,  14, 15. 

Hornblende,  43. 

Horse  in  mining,  146. 

Horse  type  in  geology,  306,  315. 

Hot  Springs  of  National  Park.  97. 

Hugi,  on  motion  of  glaciers,  31. 

Human  relics,  343. 

Hysenodon,  308. 

Hyposyenite,  44. 

Ice  in  the  soil,  121 ;  under  lava,  122 ; 
erupted  with  lava,  122. 

Iceland,  geysers  of,  100. 

Ichthyornis,  314. 

Ichthyosaur,  301,  311. 

Iguanodon,  301. 

Illinois  flooded,  48. 

Insects  of  Coal  Period,  294. 

Internal  heat,  102. 

Inversion  of  strata,  92. 

Invertebrates,  reign  of,  278  seq. 

Iron  and  its  geology,  153. 

Iron  in  earth's  center,  159. 

Joggins,  coal  beds  at,  218. 

Jurassic  mammals,  304. 

Karaboghaz.  Gulf  of,  159. 

Kazwini ,  opinions  of,  80. 

Kilauea,  eruption  of,  109  :  lava  of,  267. 

King  Crab  and  his  relatives,  234  seq. 

Knox  county  gas,  174. 

Labyrinthodonts,  218,  296, 311. 

Laccolite,  116. 

Lacustrine  deposits,  45. 

Laslaps,  302. 

Lakelets,  origin  of,  339. 

Lakes,  Tertiary,  323. 

Lakes,  the  Great,  floods  of,  45  ;  inun- 
dation by,  46,  47. 

Lamellibranchs,  237. 

Laminse,  71. 

Lamination,  71;  oblique,  71. 

Lands  of  primitive  times,  280,  283. 


Langford,  N.  P.,  on  "  Giantess  gey- 
ser," 98. 

Langley.  S.  P.,  on  solar  heat,  257. 

Lapilli,i04. 

Laurentide  Hills,  139. 

Lava  of  Vesuvius,  103. 

Lavas,  ancient,  111 ;  on  Pacific  slope, 
112, 323, 333 ;  in  interior,  113  ;  ages  of 
eruption  of,  114,  322 ;  Triassic,  300 ; 
Tertiary,  323  :  Quaternary,  334,  341. 

Lead  mines,  153\ 

Leadville  mining  district,  153. 

Lepidodendron,  215,290,  294.  295,  296. 

Lessons  from  fossil  fishes,  290. 

Levees,  55. 

Lewis,  H.  C.,  on  early  man,  343. 

Lewiston  escarpment.  48. 

Limestone,  45 ;  Devonian,  222 ;  Silur- 
ian, 229 ;  how  formed  in  primeval 
ocean,  272. 

Limonite,  154. 

Limulus,  234. 

Lingula,  236,  239,  281. 

Liquid  earth,  266. 

Lizards,  301,  312. 

Lodes,  146.    See  "  Comstock  Lode." 

Lodestone,  156. 

Lost  Rocks,  11. 

Machserodus,  308. 

Mackinac  Island,  46. 

Magnetite,  156. 

Mallet,  R.,  on  earthquakes,  127. 

Mammals,  reign  of,  84 ;  extinct  spe- 
cies of,  189  seq.,  198  seq.;  Triassic, 
303 ;  Jurassic,  304 ;  in  Bad  Lands, 
200 ;  on  Atlantic  coast,  201 ;  in  Ala- 
bama, 201 ;  Ceenozoic,  305. 

Mammoth,  190 ;  Siberian.  191, 332, 345. 

Mammoth  Hot  Springs,  100. 

Man,  reign  of,  84 ,  prophesied,  292. 

Man,  primitive,  advent  of,  340  seq.; 
antiquity  of,  341;  a  Glacial  phenom- 
enon, 343:  contemporaries  of,  345; 
characteristics  of,  346. 

Marine  Invertebrates,  reign  of,  83. 

Marl,  38. 

Marsh,  O.  C.,  on  fossil  mammals,  205, 
304 ;  on  fossil  reptiles,  213. 

Marshall  Sandstone,  290. 

Marshes,  origin  of,  53. 

Mashing  together  of  rocks,  142, 143. 

Mastodon,  190, 308. 

Mauna  Loa,  eruption  of,  109. 

Megatherium,  195. 

Meniscoessus,  304. 

Menodus,  308. 

Mesozoic,  Great  System,  84  ;  events, 
296  seq.;  rocks  and  fossils,  206  seq., 
296  seq.;  coal,  214  ;  erosions,  321. 

Metamorphism,  143, 144,  247,  279. 

Metcalf,  W.,  on  Pittsburg  gas,  177. 

Meteors,  255. 

Method  in  nature.  253, 316. 

Mica  described,  41. 

Mica  schist,  43. 


352 


Index. 


Michigan  salt,  163, 164  ;  gas,  175. 

Milwaukee  bricks,  49. 

Minerals  defined,  40. 

Mines  and  mining,  146. 

Mississippi  River,  sediments  of,  54. 

MontCenis  Tunnel,  120. 

Monti  Rossi  on  ^Etna,  107. 

Monument  Park,  63. 

Moon,  origin  of,  265 ;  tidal  action  of, 

Moraine  defined,  30;  of  continental 
glacier,  332,  335. 

Mosasaur,  211,  301. 

Moss  petrified,  38. 

Mountains,  structure  of,  132  seq.;  of 
upheaval,  137,  274  ;  erosion  of,  138  ; 
of  relief,  138;  formation  of,  139, 295 ; 
theories  of,  139;  trends  of,  143;  thick- 
ness of  strata  in,  145 ;  synclinorium 
theory  of,  145. 

Mouths  of  great  rivers,  55. 

Mud  from  Vesuvius,  105. 

Murraysvillegas  wells,  178, 180. 

Mylodon,  194, 

National  Park  described,  94  seq. 

Nautilus  and  its  ancestry,  227  seq. 

Nebul»,259,260«eg. 

Nebular  theory,  261  seq. 

Neflf,  Peter,  and  gas  production,  175. 

Nevada  continent,  320. 

Neve,  22, 328. 

Newberry,  J.  S.,  on  Table  Mt.  plants, 

New'England  reptiles,  298. 

Niagara  gorge,  48,  336. 

Niagara  Limestone,  230. 

Northern  Land  of  America,  280, 283, 
317 ;  uprising  of,  319. 

November  meteors,  256. 

Obelisk,  New  York,  44. 

Ocean  depths,  explored,  64 ;  origin  of, 
265 ;  chemical  war  In,  271  seq.;  sedi- 
mentation in,  275. 

Odontornithes,  313. 

811.    See  "  Petroleum." 
il  regions,  170. 
Old  Faithful  geyser,  97, 98. 
Oldham  on  Earthquakes,  127. 
Old  Red  Sandstone,  227. 
Onchus,  oldest  vertebrate,  287, 288. 
Onychodus,  286, 288,  309. 
Oreodon.307. 
Ores  of  iron,  38, 153  seq. 
Orthoceras,  230,  238, 282. 
Otozotim,  299, 300. 
Outcrop  defined,  78, 88. 
Oysters  in  Cretaceous  rocks,  210. 
Ozark  Range  as  an  obstacle,  48. 


Palaeozoic,  Great  System,  84 ;  popula- 
tions, 281. 

Palmieri  and  earthquakes,  103. 
Panama  clifls,  71. 
Parameryx,  307. 
Park,  National,  described,  95  seq. 


Peat,  187. 

Pebbles,  11. 

Pelagic  forms,  67. 

Perrey  on  earthquakes,  128. 

Petroleum,  geology  of,  166;  laws  of 

accumulation  of,  167. 
Pilot  Knob,  157. 
Pitttsburg  gas,  177;   production  of, 

Placers,  117. 

Placoderms,  284. 

Plantigrade  mammals,  306. 

Plants,  in  coal  beds,   184 ;   of  coal 

period  ,293. 

Plateau  Province,  322,  323. 
Plesiosaur,  301. 
Ponds  filling  up,  52. 

PotholesfsSS.' 

Potsdam  Sandstone,  136, 236,  240. 

Prairies,  origin  of,  339. 

Preadamites,  question  of,  347. 

Precipitations,  primeval,  272. 

Prophetic  types,  309. 

Protozoans,  reign  of,  83. 

Pteraspis,  286. 

Pterichthys,  287. 

Pterosaur,  302  312. 

Quartz,  and  its  varieties,  41 ;  primi- 
tive, 273. 

Quartzite,  40, 273. 

Quaternary,  mammals,  189  seq.; 
events  in  West,  323. 

Rain,  where  does  it  go  ?  32. 

Ramsay  on  lake-basins,  338. 

Reigns  of  extinct  types,  83. 

Relics  of  man,  in  river  drift,  343 ;  in 
lakes,  343;  on  shores,  344;  in  bogs, 
344. 

Relief  in  mountain  features,  62. 

Reptile  monarchy,  296. 

Reptiles  of  Cretaceous  time,  213;  of 
Mesozoic,  296  seq.;  diversification 
of  type  of,  301 ;  a  comprehensive 
type,309. 

Resolution  of  comprehensive  types, 
310. 

Retrospection  in  organic  types,  309. 

Rhynchodus,285. 

River  drifts,  343. 

River  terraces,  50. 

Rocking  stones.  15. 

Rocks,  kinds  of,  39 ;  how  distinguish- 
ed. 40. 

Rocky  Mountains  lowered,  61 ;  form- 
ing, 321. 

Rotation  of  earth  retarded.  144. 

Rotten  limestone  of  Ala.,  209. 

Salt,  geoiogy  ot,  160;  in  sundry  re- 
gions, 162 ;  impurities  of,  164. 

Sandstone,  45;  red,  of  Connecticut 
valley,  300. 

Saurians,  298  seq. 

Schist,  mica,  43 ;  hornblende,  44. 

Seaboard  Land,  280,  292, 317. 


Index. 


353 


Seaweeds,  fossil.  230.  |  Systems  of  strata,  83,  84. 

Sedimentation,  51 ;  in  ocean,  275 ;  re-  i  Table  Mountains,  116. 

stricted 
Sedimen 

pond 


id  to  continental  slopes,  275.  Table  of  geological  history,  85. 
ats,  assortment  of,  52 ;  filling  Terminal  moraines  of  cont 
,  52 ;  in  river  waters,  54 ;  thin-  '  glaciers,  330  seq. 


ner  under  deep  waters,  277 ;  'trans- 
portation of,  56 ;  on  ocean  bottom, 
64,65. 

Segregations  of  ore,  157. 

8£racs,  26. 

Shale,  45. 

Sharks,  284. 

Sherman,  General,  on  "  Old  Faith- 
ful," 98. 

Shrinking  of  earth,  131.  See  "  Con- 
traction." 

Siberian  mammoth,  191. 

Siderite,  158. 

§ierra  Nevada  uplifted,  321. 
igillaria,  215,  219,290,  294,  296. 

Silurian,  83 ;  rocks,  228 ;  fossils,  230 
seq. 

Sinter,  silicious,  97. 

Skaptar  Jokul,  eruption  of,  109. 

Smith,  J.  L.,  on  gas  wells,  178. 

Soluble  substances  in  Drift,  36. 

Somma,  on  Vesuvius,  104,  111. 

South  American  quadrupeds,  195. 

Spirifera,  225. 

Springs  and  wells,  34, 35 ;  in  National 
Park,  97  seq. 

Stigmaria.215. 

St.  Peters  Sandstone,  240. 

Storm,  primeval,  265. 

Strains  from  shrinkage,  131,  291,  300. 

Strata,  and  classifications,  71 ;  exam- 
ples of,  73,  74;  formed  by  water, 
75 ;  not  in  deep  sea,  76 ;  oldest  not 
yet  seen,  87;  arrangement  of,  88; 
often  in  long  folds,  92 ;  situation  of 
newest.  93. 

Stratified  and  unstratifled,  43, 71. 

Streams,  sources  of,  35. 

Structure,   geological  explained,  88, 

Submergence  of  Quaternary,  334. 
Subterranean  waters,  32. 
Sugar  Loat,  Mackinac,  47. 
Sun,  a  remnant  of  fire-mist,  265. 
Sun's  heat  in  the  soil,  118. 
Sutro  tunnel,  150. 
Swamps,  origin  of,  53. 
Swarms,  meteoroidal,  259. 
Syenite,  43 ;  formation  of,  279. 
Symmetry,  two  kinds  of,  237. 
Synclinal  explained,  89. 


continental 

Terraces  of  lakes,  46 ;  of  rivers,  50, 
337. 

Tertiary  mammals,  206. 

Tides  in  primitive  history  of  earth, 
265  seq.,-  in  reptilian  age,  299. 

Till  defined,  19,  335,  343. 

Tillotherium,  307. 

Tinoceras.  307. 

Torrential  action,  20. 

Tracks  in  sandstone,  298,  299. 

Translation,  earthquake  of,  129. 

Transportation  of  Drift,  13. 

Trap  eruptions  in  Trias,  300. 

Travertine,  38 ;  deposited  by  geysers, 
99. 

Trends  of  mountain  axes,  143. 

Triassic,  lavas.  114 ;  sandstones,  213 ; 
mammals,  303. 

Trilobites,  235 ;  Cambrian,  281. 

Tube  of  a  geyser,  97. 

Tufa,  38. 

Uinta  Mountains  upraised,  322. 

Uintatherium,  307. 

Uplifts  of  strata,  142. 

Vapor  defined,  250. 

Vegetation  of  coal  beds,  184,  215 ;  of 
Cretaceous,  210 ;  of  Eozoic,  279. 

Veins  of  ores,  157. 

Vertebrates,  earliest,  283. 

Vesuvius,  103 ;  eruptions  of,  105. 

Vibration,  earthquakes  of,  129. 

Vogt,  Carl,  on  Archseopteryx,  312. 

Volcanic  eruptions  of  far  west,  323. 

Volcanoes,  103  seq.,  323;  and  earth- 
quakes, 129, 130. 

Wahsatch.  319,  320. 

Warm  springs,  96,  99  seq. 

Wastage  of  the  land,  62, 326. 

Wasted  continental  surface,  326. 

Water-basins  in  the  earth,  33. 

Water,  first  condensation  of,  269. 

Waverly  Sandstone,  290. 

Waves  of  earthquakes,  126. 

Wells  and  springs,  34, 35. 

Widder.  fossils  at,  225. 

World,  has  been  built,  9. 

World-stuff,  253.  See  "  Cosmic  dust." 

Wrinkling  of  strata,  142, 274,  295. 

?akutsk,  frozen  soil  at,  121. 
ellowstone  Lake,  95. 
Zeuglodon,202. 


This  book  is  DUE  on  the  last  date  stamped  below 


WAR  \  8 


AW 

APR  2  0  1967 
JAN  2  8  1991 


Form  L-9-35m-8,'2£ 


The  RALPH  D.  REED  LIBftAR* 

DEPARTMENT  OF  GEOLOGY 

UNIVERSITY  of  CALIFORNIA 
LOS  ANGELES.  CALIF. 


UNIVERSTTY  of  CALIFORNIA 


vNGELES 

I  fRRARY 


